) Suppose a statistics instructor believes that there is no difference between the mean test scores of students taking a morning class and students taking an afternoon class. She takes a sample from each of her classes, one morning and one afternoon. The mean and standard deviation for 40 morning students (sample 1) were 78.7 and 19.9, respectively. The mean and standard deviation for 45 afternoon students (sample 2) were 81.8 and 17.5. Using????

=0.05, determine if there is a difference between the average test scores of morning and afternoon students.

Hypotheses

What is the null hypothesis?

mu

x-bar

p

p-hat

mu_1

p_1

mu_2

p_2

=

>=

<=

=/=

>

<

mu

x-bar

p

p-hat

mu_1

p_1

mu_2

p_2

What is the alternative hypothesis?

mu

x-bar

p

p-hat

mu_1

p_1

mu_2

p_2

=

>=

<=

=/=

>

<

mu

x-bar

p

p-hat

mu_1

p_1

mu_2

p_2

Test Statistic

z or t

z

t

=(round to 4 decimal places)

p-Value

p =(round to 4 decimal places)

Conclusion

Reject / fail to reject

Reject

Fail to reject

????

0

H0There

is / is not

is

is not

sufficient evidence to conclude that the mean test score for the morning class is

less than / greater than / different from

less than

greater than

different from

that of the afternoon class.