Answer to Question #181677 in Statistics and Probability for Mads Mendes

Question

State the null hypothesis and the alternative hypothesis in (a) words and in 

(b) symbols for each of the following. 

a. A librarian of a school claims that all their grade 8 students read an 

average of 10 storybooks a month with a standard deviation of 2 books. 

A random sample of grade 8 students read an average 12 books a month 

and a standard deviation of 1 book. The confidence statement is 95%. 

b. According to a factory employer, the mean working time of workers in 

the factory is 6 hours with a standard deviation of 0.5 hours. A 

researcher interviewed 50% of the employees and found out that their 

mean working time is 8 hours with a standard deviation of 1 hour. The a 

level is 0.05. 

Answer 1

a)

H₀: all the grade 8 students read an average of 10 storybooks a month

H_a: the grade 8 students do not read an average of 10 storybooks a month

H₀: μ = 10

H_a: μ ≠ 10

b)

H₀: the mean working time of workers in the factory is 6 hours

H_a: the mean working time of workers in the factory is not 6 hours

H₀: μ = 6

H_a: μ ≠ 6