Question

1-An educational psychologist hypothesized that children are
inclined to **lose** interest in school as they
progress through the elementary grades. In order to test this
hypothesis, the psychologist randomly selects a sample of
*n* = 30 first-grade children and a sample of *n* =
30 fourth-graders. Each participant is given a survey measuring
his/her interest in school. Higher scores indicate a more positive
interest in school.

The first grade students had a mean school interest of 25 with a standard deviation of 2.5, and the fourth grade students had a mean school interest of 22 with a standard deviation of 3.

What is the null hypothesis for this scenario?

a)The average interest in education among fourth graders is greater than or equal to 25

b)The average interest in education among fourth graders is less than or equal to 25

c)The average interest in education among fourth graders is less than 25

d)The average interest in education among first graders is greater than or equal to 25

2-True or False, z-distributions are used for means?

3-True or False, The **significance level**
(represented as α, or the α-level) represents the maximum
probability we are willing to accept for making a false negative
(Type II) error.

Answer #1

given that

first grade students had a mean school interest of 25 with a standard deviation of 2.5, and the fourth grade students had a mean school interest of 22 with a standard deviation of 3.

1)

we have to test that if the mean school interest for grade 1 is greater than mean school interest for grade 4

here our research hypothesis is mean school interest for grade 4 is less than that of grade 1

so our null hypothesis should be stated as " mean school average for grade 1 is less than or equal to that of grade 4"

Hence

option (A) is correct

2)

since here we have population standard deviation hence we will Z statistics hence

it TRUE

3)

since level of significance is defined as probability of rejecting H0 falsely that is level of significance is defined as probability of making type 1 error or false positive result.

Hence its FALSE

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