Question

jeanette took two tests. find her z - score for each test. (remember: the number of standard deviations between a score and the mean score is indicated by a z - score.) on which did she score better compared with others in her class?
test a test b
jeanettes score 90 95
mean score 64 60
standard deviation 8 10
a. test a: 3.25; test b: 3.5; test b
c. test a: 26; test b: 35; test b
b. test a: 3.5; test b: 3.25; test a
d. test a: 3.25; test b: 3.5; test a
please select the best answer from the choices provided
a
b
c
d

Explanation:

Step1: Calculate \(z -\)score for Test A

The formula for \(z -\)score is \(z=\frac{x-\mu}{\sigma}\), where \(x\) is the individual score, \(\mu\) is the mean, and \(\sigma\) is the standard deviation.
For Test A: \(x = 90\), \(\mu=64\), \(\sigma = 8\)
\(z_A=\frac{90 - 64}{8}=\frac{26}{8}=3.25\)

Step2: Calculate \(z -\)score for Test B

For Test B: \(x = 95\), \(\mu = 60\), \(\sigma=10\)
\(z_B=\frac{95 - 60}{10}=\frac{35}{10}=3.5\)

Step3: Compare \(z -\)scores

Since \(z_B=3.5>z_A = 3.25\), a higher \(z -\)score means the score is better compared to the class.

Answer:

A. Test A: 3.25; Test B: 3.5; Test B