Question

A newspaper article says that on the average, college freshmen spend 7.5 hours a week going to parties.14 One administrator does not believe that these figures apply at her college, which has nearly 3,000 freshmen. She takes a simple random sample of 100 freshmen, and interviews them. On average, they report 6.6 hours a week going to parties, and the SD is 9 hours. Is the difference between 6.6 and 7.5 real? (a) Formulate the null and alternative hypotheses in terms of a box model. (b) Fill in the blanks. The null says that the average of the box is . The alternative says that average of the box is . (c) Now answer the question: is the difference real?

Answer 1

Answer:

a.

The hypothesis Null and alternative can be formulate as a :

H0 = μ = 7.5 hr / week

Hₐ = μ < 7.5 hr / week

b.

The Null hypothesis is true and the administrator believes that the college freshman dot not spend 7.5 hours

E(x) = μ = 7.5 hr / week

SE (x) = σ / √ n = 9 / √100

SE (x) = 0.9

Z' = 6.6 - 7.5 / SE

Z' = 6.6 -7.5 / 0.9 = -1  

The empirical rule in this case is use

% = (100 - 68 ) / 2 = 16%

c.

There is not strong arguments of Null Hypothesis so can be accept the H0 and is no significantly different from the report of 7.5 hr / week