Exam 8: Introduction to Inferential Statistics

A researcher is interested in whether students who are musicians have higher intelligence test scores than students in the general population. The researcher predicts that playing a musical instrument is associated with higher intelligence test scores. The researcher selects a sample of 75 musicians from local high schools and gives them an intelligence test. She compares their average intelligence to that of students in the general population and finds that z_obt = +1.92. This is a _____ test and the researcher should conclude _____.​

Assume that the average person in America weighs 150 pounds (m). You want to determine whether college students weigh less than the average American. Following are the weights collected on a sample of college students: 120, 105, 166, 170, 145, 149, 135, 115, 168, 138. ​

z_cv for a one-tailed test is _____ whereas z_cv for a two-tailed test is _____.

A _____-tailed test and a _____ sample size will both increase the power of the test.​

In order to increase the power of z test, one might

What is the standard error of the mean for a distribution of scores where s = 24 and n = 144?

A researcher is interested in whether students who are musicians have higher intelligence test scores than students in the general population. The researcher predicts that playing a musical instrument is associated with higher intelligence test scores. This is a _____-tailed test and the z_cv is _____.

If a researcher reported for a one-tailed single-sample t test that t(14) = 2.25, then​

The standard error of the mean is calculated by dividing _____ by _____.​

Given: For one section of the SAT: m = 500 and s = 100. The SAT was given to a sample of n=35 and the mean SAT for this sample was 536. Calculate the z test for this sample mean. Does this sample differ significantly from the population for a two-tailed test?​

Explain why  decreases as the size of the samples in the sampling distribution increase. Your answer should include an explanation based on the formula for  and an explanation of why this formula makes sense (in other words, why would increasing the size of each sample in the sampling distribution cause  to decrease?

What is the standard error of the mean for a distribution of scores where s = 15 and n = 100?

The _____ distribution is a set of distributions that, although symmetrical and bell-shaped, are not normally distributed.​

A parametric inferential statistical test of the null hypothesis for a single sample where the population variance is known is the​

For a single-sample t test with 10 participants, the degrees of freedom are​

A researcher is interested in whether 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). This is a _____ -tailed test and the z_cv is _____.

When comparing a sample to a population, if you know m and s and have a sample size larger than 30, you should conduct a _____ test. ​

A researcher is 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 (s) of 3. What is z_obt for this sample?​