A researcher in interested in whether high school students who play sports have a higher or lower body mass index (BMI)than students in the general population.The researcher is unsure whether playing sports will decrease body mass (due to more calories burned)or increase body mass (due to more muscle mass).The researcher selects a sample of 60 athletes and finds that their average BMI is 22.The average (µ)in the general population of students is 22.5 with a standard deviation ($\sigma$)of 3.What is z_obt for this sample? A).98 B)1.29 C)1.96 D)2.25

Question

Quizplus · Accepted Answer

z-score formula: z = (sample mean - population mean) / (population standard deviation / square root of sample size)

z = (22 - 22.5) / (3 / sqrt(60))
z = -0.5 / 0.3873
z = -1.29

The z-score is -1.29, so the answer is B.

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