Questions from Essentials of Statistics

Q: Under what circumstances is a t statistic used instead of a z

Under what circumstances is a t statistic used instead of a z-score for a hypothesis test?

Q: Suppose that a researcher is interested in whether an exercise improves intelligence

Suppose that a researcher is interested in whether an exercise improves intelligence. The researcher randomly selects 100 participants, assigns them to an exercise program, and measures intelligence a...

Q: A sample of n = 25 scores has a mean of M

A sample of n = 25 scores has a mean of M = 200 and a variance of s2 = 100. a. Explain what is measured by the sample variance. b. Compute the estimated standard error for the sample mean and explain...

Q: Find the estimated standard error for the sample mean for each of

Find the estimated standard error for the sample mean for each of the following samples. a. n = 9 with SS = 1,152 b. n = 16 with SS = 540 c. n = 25 with SS = 600

Q: The following sample of n = 7 scores was obtained from a

The following sample of n = 7 scores was obtained from a population with unknown parameters. Scores: 2, 18, 15, 5, 15, 8, 7. a. Compute the sample mean and variance. (Note: These are descriptive value...

Q: Explain why t distributions tend to be flatter and more spread out

Explain why t distributions tend to be flatter and more spread out than the normal distribution.

Q: Find the t values that form the boundaries of the critical region

Find the t values that form the boundaries of the critical region for a two-tailed test with α = .05 for each of the following sample sizes: a. n = 6 b. n = 12 c. n = 48 d. Repeat parts a–c assuming a...

Q: Describe the basic characteristics that define an independent-measures, or

Describe the basic characteristics that define an independent-measures, or a between-subjects, research study.

Q: Describe the homogeneity of variance assumption and explain why it is important

Describe the homogeneity of variance assumption and explain why it is important for the independent measures t test.

Q: A research study comparing alcohol use for college students in the United

A research study comparing alcohol use for college students in the United States and Canada reports that more Canadian students drink but American students drink more (Kuo, Adlaf, Lee, Gliksman, Demer...