Question

2) Natalie is interested in the money which people spend on textbooks. She obtained mean of $100 that has a SD of $30 in a sample of 121 students. What’s her 99% CI of the mean?

A. [40.00, 160.00] B. [94.66, 105.34] C. [95.42, 104.58] D. [92.98, 107.02]

3) A researcher selects a sample of 1000 participants from a population with a mean of 81 and a standard deviation of 10. About 99% of the sample means in this sampling distribution should be between a sample mean of ______.

A. 80.19 and 81.81 B. 80.38 and 81.62 C. 80.48 and 81.52 D. 51.00 and 111.00

Answer 1

since in both case sample size is large enough that is greater than 30 so we use here Z statistics in C.I.

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