Since your population are the students in math class, you can use the z-score formula $z=(x-\mu)/\sigma$ in order to comparing the two math test scores. Where $\mu$ is the mean for the class, $\sigma$ is the standars deviation and x is Mary score.

For the first test $\mu=.71 , \sigma=.18,x=.87$ , so , $z_{1} = (.87-.71)/(.18)=.88$ .

For the second test $\mu=.53 , \sigma=.14,x=.66$ , so , $z_{1} = (.66-.53)/(.14)=.93$

Mary do better in the second test, relative to the rest of the class (because $.88 \leq .93$ , it means the second score is nearer to the mean score of the class than the first one )

6 0

4 years ago

A spinner is divided into 20 equal sections. what is the probability of the spinner's pointer landing on section 5?

marta [7]

1/20 would be the correct answer

3 0

4 years ago

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How many fifths are there in 8 3/5?​

How many fifths are there in 8 3/5?