Question 1

The standard error of the average is determined by dividing the standard deviation from the same sample that yielded the average by the square root of the sample size.

Accepted Answer

The formula for the standard error of the mean is the sample standard deviation divided by the square root of the sample size. So, the statement is true.

Question 2

With a hypothesis test, if the z value falls outside the acceptance region than we say there is no support for alternative hypothesis.

Accepted Answer

If the z value falls outside the acceptance region, it indicates that there is support for the alternative hypothesis, suggesting that the null hypothesis can be rejected.

Question 3

A practical use of confidence intervals is that they may be used to forecast best, pessimistic, and optimistic market-potential estimates..

Accepted Answer

Confidence intervals provide a range of possible values for an unknown population parameter, such as the mean of a market potential estimate. By using the upper and lower bounds of the confidence interval, one can make best, pessimistic, and optimistic market-potential estimates. Therefore, confidence intervals can be a practical tool for forecasting market potential.

Question 4

Forming a directional hypothesis means that we are still seeking a direction for the hypothesis.

Accepted Answer

Forming a directional hypothesis means that we have a specific direction in mind, either a positive or negative relationship between variables.

Question 5

The standard error is a measure of the variability in a sample based on the variability found in the population.

Accepted Answer

The standard error is a measure of the variability in a sample based on the variability found in the sample, not the population.

Question 6

Intuitive testing is another name for hypothesis testing.

Accepted Answer

Intuitive testing refers to the process of using one's intuition or personal judgment to identify issues or bugs in a product or system, while hypothesis testing involves creating and testing a specific hypothesis or assumption about the product or system. They are not the same thing.

Question 7

Market potential can be determined by multiplying the population base by the percent willing to buy by the amount they are winning to spend.

Accepted Answer

Market potential can be calculated by multiplying the population base with the percentage of people who are willing to buy the product or service, and the amount they are willing to spend. This formula gives an estimate of the maximum revenue that can be generated by a particular market.

Question 8

The z value is agreed by statisticians to be more proper than the t value when the sample is large.

Accepted Answer

When the sample size is large (typically n > 30), the distribution of sample means approaches a normal distribution regardless of the population distribution. In this case, the z-value can be used as the standard error of the mean, which is more appropriate than the t-value. The t-value is only necessary when the sample size is small or the population standard deviation is unknown.

Question 9

Sample information is invariably more accurate than a hypothesis.

Accepted Answer

Sample information refers to data or observations obtained from a specific group or population. This information is based on reality and can be objectively verified. On the other hand, a hypothesis is an educated guess or a proposed explanation for a phenomenon that requires further testing and validation. While a hypothesis may be grounded in existing knowledge and can guide research, it is not yet confirmed or proven. Therefore, sample information is typically more accurate than a hypothesis because it is based on actual observations rather than speculative reasoning.

Question 10

When a statement about the population parameter is made based on prior knowledge, assumptions, or intuition, this is a hypothesis.

Accepted Answer

This is because a hypothesis is a statement or claim about a population parameter that is made without any evidence or data yet to support it. It is based on prior knowledge, assumptions, or intuition.

Question 11

When estimating a population parameter for a categorical question we need to first calculate the sample mean.

Accepted Answer

When estimating a population parameter for a categorical question, we need to calculate the sample proportion or percentage instead of the sample mean.

Question 12

You test a directional hypothesis that consumers spend less than $12 a person to go to the movies. Your z value turns out to be -1.75 at a 95% confidence interval. Your data supports your hypothesis.

Accepted Answer

The answer of You test a directional hypothesis that consumers...

Question 13

The standard error is a measure of the variability in the sampling distribution based on what is believed would occur if a multitude of independent samples were taken from the same population.

Accepted Answer

The statement accurately describes the concept of standard error.

Question 14

Directional hypotheses contain statements of "greater than" or "less than."

Accepted Answer

Directional hypotheses are used when the researcher has a specific prediction about the direction of the relationship between variables. This prediction is stated as "greater than" or "less than". Therefore, directional hypotheses contain statements of "greater than" or "less than".

Question 15

The logic of hypothesis testing is that if we assume that the hypothesized value is the population parameter, then, at the 95 percent level of confidence, if we took 100 separate samples, the z value for 95 of those samples would fall between + 1.96.

Accepted Answer

This statement accurately describes the logic and interpretation of a 95% confidence interval.

Question 16

Hypothesis testing is a statistical procedure used to accept or reject the hypothesis, based on sample information.

Accepted Answer

Hypothesis testing is indeed a statistical procedure used to accept or reject the hypothesis, based on sample information.

Question 17

The null hypothesis refers to doing just about anything to make a decision other than hypothesis testing.

Accepted Answer

The null hypothesis is a concept specifically related to hypothesis testing in statistics.

Question 18

The critical z value for a directional hypothesis test is adjusted downward to 1.46 from 1.96 for the 95% confidence level.

Accepted Answer

For a directional (one-tailed) hypothesis test at a 95% confidence level, the critical z value is 1.645, not 1.46. The value 1.96 is used for a two-tailed test.

Question 19

If we are testing a hypothesis that a sample mean does not differ from a hypothesized value at the 95 percent level of confidence, and we arrive at a z value of 1.99, we would fail to support the hypothesis.

Accepted Answer

A z value of 1.99 corresponds to a p-value of approximately 0.05, which is the cutoff for rejecting the null hypothesis at the 95% confidence level. Therefore, we would reject the hypothesis and conclude that the sample mean does differ from the hypothesized value.

Question 20

With all hypothesis tests, the sample is the only source of current information about the population.

Accepted Answer

Hypothesis tests are conducted using sample data to make inferences about the population parameters. This is because it is usually impractical or impossible to obtain information about the entire population, and the sample is the best representation of the population that is available. Therefore, the sample is the only current source of information about the population when conducting hypothesis tests.

Quiz 11: Population Estimates and Hypothesis Testing