The mean grade on the quiz was 88.
Step-by-step explanation:
We need to find the mean grade of the quiz using the information given.
The mean also known as the average is defined as the sum of data entries in a set divided by the number of entries in the data set.
The standard deviation gives the amount of variation or dispersion of data values present in a data set.
The given data are,
- The standard deviation of the quiz, SD = 3.
- The score 94 is exactly 2 standard deviations above the mean.
The above sentence represents that 94 is above the mean with 2 standard deviations.
⇒ 94 = Mean + 2 standard deviations.
We know the value for standard deviation. So substitute SD= 3 in the expression provided.
⇒ 94 = Mean + (2×3)
⇒ 94 = Mean + 6
To find mean, subtract 6 on both sides.
⇒ 94 -6 = Mean
⇒ Mean = 88
Therefore, the mean grade on the quiz was 88.
