Answer :
Solution: We are given:
[tex]Mean =78, Standard-deviation =6.3[/tex]
We know that a usual values of the test scores falls within 2 standard deviation from the mean.
Therefore, the minimum usual test score is:
[tex]Mean - 2 Standard-deviation[/tex]
[tex]78-2 \times 6.3[/tex]
[tex]78-12.6[/tex]
[tex]65.4[/tex]
The maximum usual test score is:
[tex]Mean + 2 Standard-deviation[/tex]
[tex]78+2 \times 6.3[/tex]
[tex]78+12.6[/tex]
[tex]90.6[/tex]
Therefore, the minimum and maximum “usual” values of the test scores are:
65.4 and 90.6
Answer:
The minimum and maximum usual value of the test scores are:
65.4 and 90.6
Step-by-step explanation:
We know that:
The maximum usual value is two standard deviations above the mean and the minimum usual value is two standard deviation below the mean.
i.e.
Maximum value= Mean+2×standard deviation.
i.e. Maximum value= 78+2×6.3
Maximum value= 90.6
and
Minimum value= Mean-2×standard deviation.
Minimum value= 78-2×6.3
i.e. Minimum value= 65.4
