STAT 2040 Study Guide - Quiz Guide: Normal Distribution, Sampling Distribution, Type I And Type Ii Errors

One term, about 700 Statistics 2 students at the University of California, Berkeley, were asked how many college mathematics courses they had taken, other than Statistics 2. The average number of courses was about 1.1; the SD was about 1.5. Would the histogram for the data look like (i), (ii) or (iii)?

(i)

(ii)

(iii) 

The percent of science students (other than students in Mathematics and Statistics) who are doing a minor in statistics is 20%. If 300 students are selected what is the approximate probability that a) more than 150 are taking a minor in statistics b) between 40 and 70 are taking a minor in statistics c) exactly 50 are taking a minor in statistics. 

A survey in 2010 showed that college students study for a statistics exam on average for three hours and ten minutes. To determine if the average time is changed for the statistics exam data gathered from 81 students in a Midwest University. The sample showed that the average studying time for a statistics exam is two hours and fifty minutes with a standard deviation of one hour and thirty minutes. Let .

a. State the null and alternative hypothesis to be tested.

b. Identify the level of significance.

c. Identify the test statistics.

d. Determine the critical value for this test and formulate a decision rule using the critical value.

e. Compute the test statistics.

f. What do you conclude? Interpret the results.