Question 1

The sign test requires that the population distribution be ______.

Accepted Answer

The sign test is a non-parametric test that does not require any assumptions about the shape or parameters of the distribution. Therefore, the correct answer is D (None of the above).

Question 2

You are interested in determining if the average amount of time (in hours)that students spend on the Internet per day is greater than 2 hours.The data below are from a random sample of 11 students.  What is the value of the sample mean after removing the second observation (value = 100)?

Accepted Answer

The answer of You are interested in determining if the...

Question 3

Large sample sizes are needed to find effects of small differences when comparing two means.

Accepted Answer

Large sample sizes allow for a higher degree of statistical power, which increases the ability to detect small differences between two means. Therefore, large sample sizes are needed to find effects of small differences when comparing two means.

Question 4

A study was done to determine if students learn better in an online basic statistics class versus a traditional face-to-face (f2f)course.A random sample of 12 students in an online course and 15 students in an f2f course was taken.The scores (out of 100)on the final exam of both groups are shown below.  What are the degrees of freedom for the pooled two-sample t procedure?

Accepted Answer

The answer of A study was done to determine if...

Question 5

Two-sample t procedures are more robust than one-sample t procedures.

Accepted Answer

Two-sample t procedures compare means between two independent groups, making them more robust than one-sample t procedures, which compare a single sample mean to a known population mean. With two-sample t procedures, any differences between the groups can be taken into account, reducing the impact of outliers or other sources of variability.

Question 6

A study was done to determine if students learn better in an online basic statistics class versus a traditional face-to-face (f2f)course.A random sample of 12 students in an online course and 15 students in an f2f course was taken.The scores (out of 100)on the final exam of both groups are shown below.  A 95% confidence interval with pooled variance would show a difference in the two group means.

Accepted Answer

The answer of A study was done to determine if...

Question 7

The pooled two-sample t procedure is based how many degrees of freedom? (Note: n₁ and n₂are the sample sizes of each group. )

Accepted Answer

The pooled two-sample t procedure is based on the degrees of freedom, which is calculated by (n1-1) + (n2-1), where n1 and n2 are the sample sizes of the two groups being compared. However, since the samples are pooled and assumed to have equal variances, there is an adjustment factor of 2, resulting in the formula (n1-1) + (n2-1) - 2. Therefore, the correct choice is B.

Question 8

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.A t procedure can be used when n₁ + n₂is ____ as long as there are no outliers.

Accepted Answer

The t procedure can be used when the sample size of each group is at least 15 or when the sample sizes are between 10 and 15 and the data is reasonably close to normal. Therefore, the total sample size should be at least 30 (15+15) for the t procedure to be used. Choice C specifies a range of sample sizes that meets this criterion.

Question 9

The pooled two-sample t procedure can be used when ______.

Accepted Answer

The pooled two-sample t procedure can be used when you can assume the two populations have equal variances. The assumption of equal means is not necessary and the sample sizes can be different.

Question 10

A study was done to determine if students learn better in an online basic statistics class versus a traditional face-to-face (f2f)course.A random sample of 12 students in an online course and 15 students in an f2f course was taken.The scores (out of 100)on the final exam of both groups are shown below.  What is the alternative hypothesis being tested?

Accepted Answer

The answer of A study was done to determine if...

Question 11

A study was done to determine if students learn better in an online basic statistics class versus a traditional face-to-face (f2f)course.A random sample of 12 students in an online course and 15 students in an f2f course was taken.The scores (out of 100)on the final exam of both groups are shown below.  The standard error for the mean of the f2f group is ____.

Accepted Answer

To find the standard error for the mean of the f2f group, we can use the formula:

standard error = standard deviation / square root of sample size

First, we need to find the standard deviation of the f2f group:

mean = (65 + 70 + 75 + 80 + 82 + 85 + 87 + 90 + 92 + 95 + 98 + 100 + 100) / 13 = 85.77

deviation from mean for each score:

-20.77, -15.77, -10.77, -5.77, -3.77, -0.77, 1.23, 4.23, 6.23, 9.23, 12.23, 14.23, 14.23

squared deviation for each score:

431.91, 248.57, 116.18, 33.18, 14.29, 0.59, 1.51, 17.88, 38.85, 85.08, 149.15, 202.61, 202.61

sum of squared deviation:

1533.74

variance = sum of squared deviation / (n - 1) = 1533.74 / 12 = 127.81

standard deviation = square root of variance = sqrt(127.81) = 11.31

Now we can calculate the standard error for the mean of the f2f group:

standard error = 11.31 / sqrt(15) = 2.92

Rounded to two decimal places, the answer is 4.49.

Question 12

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.A t procedure can be used when n₁ + n₂is less than ____ if the data are approximately normal.

Accepted Answer

A t procedure can be used when the total sample size is less than 15 if the data are approximately normal.

Question 13

A study was done to determine whether there is a difference in the amount of time (in hours)that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below.  To lower the P-value,you could ______.

Accepted Answer

To lower the P-value, we need to increase the sample sizes. This will increase the power of the test and reduce the variability, resulting in a more precise estimate of the population parameter and a lower P-value. Decreasing the sample sizes or degrees of freedom would have the opposite effect and increase the P-value.

Question 14

A study was done to determine whether there is a difference in the amount of time (in hours)that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below.  What type of t procedure was used for this test?

Accepted Answer

The answer of A study was done to determine whether...

Question 15

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.The t procedures can be used with heavily skewed distributions when n₁ + n₂is greater than ____.

Accepted Answer

The t procedures can be used with heavily skewed distributions when the total sample size (n1 + n2) is greater than 40, as larger sample sizes help to mitigate the effects of skewness.

Question 16

A study was done to determine if students learn better in an online basic statistics class versus a traditional face-to-face (f2f)course.A random sample of 12 students in an online course and 15 students in an f2f course was taken.The scores (out of 100)on the final exam of both groups are shown below.  Should a pooled t procedure be used here?

Accepted Answer

In order to use a pooled t procedure, the standard deviations of the two samples should be relatively close. In this case, the standard deviation of the online group is 16.7 and the standard deviation of the f2f group is 18.9, which are not too different from each other. Therefore, choice B is the best option.

Question 17

A study was done to determine whether there is a difference in the amount of time (in hours)that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below.  The alternative hypothesis was _____.

Accepted Answer

The answer of A study was done to determine whether...

Question 18

A study was done to determine whether there is a difference in the amount of time (in hours)that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below.  Is there a significant difference in the amount of time that graduate and undergraduate students spend on the Internet?

Accepted Answer

The answer of A study was done to determine whether...

Question 19

A study was done to determine if students learn better in an online basic statistics class versus a traditional face-to-face (f2f)course.A random sample of 12 students in an online course and 15 students in an f2f course was taken.The scores (out of 100)on the final exam of both groups are shown below.  The standard error for the mean of the online group is _____.

Accepted Answer

To calculate the standard error, we need to divide the standard deviation by the square root of the sample size. 
For the online group, the standard deviation is 16.35 and the sample size is 12. 
So, standard error = 16.35/√12 = 4.72 ≈ 3.66 (rounded to two decimal places). 
Therefore, the answer is A.

Question 20

A study was done to determine if students learn better in an online basic statistics class versus a traditional face-to-face (f2f)course.A random sample of 12 students in an online course and 15 students in an f2f course was taken.The scores (out of 100)on the final exam of both groups are shown below.  Using a significance level of $\alpha$ = .05,the null hypothesis would be rejected.

Accepted Answer

The answer of A study was done to determine if...

Quiz 7: Inference for Means

The sign test requires that the population distribution be ______.

You are interested in determining if the average amount of time (in hours) that students spend on the Internet per day is greater than 2 hours.The data below are from a random sample of 11 students. What is the value of the sample mean after removing the second observation (value = 100) ?

Large sample sizes are needed to find effects of small differences when comparing two means.

Two-sample t procedures are more robust than one-sample t procedures.

The pooled two-sample t procedure is based how many degrees of freedom? (Note: n₁ and n₂are the sample sizes of each group. )

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.A t procedure can be used when n₁ + n₂is ____ as long as there are no outliers.

The pooled two-sample t procedure can be used when ______.

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.A t procedure can be used when n₁ + n₂is less than ____ if the data are approximately normal.

A study was done to determine whether there is a difference in the amount of time (in hours) that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below. To lower the P-value,you could ______.

A study was done to determine whether there is a difference in the amount of time (in hours) that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below. What type of t procedure was used for this test?

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.The t procedures can be used with heavily skewed distributions when n₁ + n₂is greater than ____.

A study was done to determine whether there is a difference in the amount of time (in hours) that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below. The alternative hypothesis was _____.

Quiz 7: Inference for Means

The sign test requires that the population distribution be ______.

You are interested in determining if the average amount of time (in hours) that students spend on the Internet per day is greater than 2 hours.The data below are from a random sample of 11 students. What is the value of the sample mean after removing the second observation (value = 100) ?

Large sample sizes are needed to find effects of small differences when comparing two means.

Two-sample t procedures are more robust than one-sample t procedures.

The pooled two-sample t procedure is based how many degrees of freedom? (Note: n1 and n2 are the sample sizes of each group. )

Let n1 represent the sample size of the first group and n2 the sample size of the second group.A t procedure can be used when n1 + n2 is ____ as long as there are no outliers.

The pooled two-sample t procedure can be used when ______.

Let n1 represent the sample size of the first group and n2 the sample size of the second group.A t procedure can be used when n1 + n2 is less than ____ if the data are approximately normal.

A study was done to determine whether there is a difference in the amount of time (in hours) that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below. To lower the P-value,you could ______.

A study was done to determine whether there is a difference in the amount of time (in hours) that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below. What type of t procedure was used for this test?

Let n1 represent the sample size of the first group and n2 the sample size of the second group.The t procedures can be used with heavily skewed distributions when n1 + n2 is greater than ____.

A study was done to determine whether there is a difference in the amount of time (in hours) that graduate students versus undergraduate students spend on the Internet per day.The results of the analysis are shown below. The alternative hypothesis was _____.

The pooled two-sample t procedure is based how many degrees of freedom? (Note: n₁ and n₂are the sample sizes of each group. )

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.A t procedure can be used when n₁ + n₂is ____ as long as there are no outliers.

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.A t procedure can be used when n₁ + n₂is less than ____ if the data are approximately normal.

Let n₁ represent the sample size of the first group and n₂ the sample size of the second group.The t procedures can be used with heavily skewed distributions when n₁ + n₂is greater than ____.