Question

A teacher wants to see if a new unit on taking square roots is helping students learn. She has five randomly selected students take a pre-test and a post test on the material. The scores are out of 20. Has there been improvement? (pre-post) Find the standard error. Student 1 2 3 4 5 Pre-test 11 9 10 14 10 Post- Test 18 17 19 20 18 Group of answer choices 0.51 -3.4 1.14 -7.6

Answer 1

0.51

Explanation:

Subtract the post from the pre:

`\left[\begin{array}{cccccc}Student&1&2&3&4&5\\Pre-test&11&9&10&14&10\\Post-test&18&17&19&20&18\\Pre-Post&-7&-8&-9&-6&-8\end{array}\right]`

The mean of the differences is:

μ = (∑x)/n

μ = (-7−8−9−6−8)/5 = -7.6.

The standard deviation is:

s = √([∑(x−μ)] / (n−1))

s = √([(-7+7.6)²+(-8+7.6)²+(-9+7.6)²+(-6+7.6)²+(-8+7.6)²] / (5−1))

s = 1.14

The standard error is:

SE = s / √n

SE = 1.14 / √5

SE = 0.51