Question

The speed of 10 cars on a certain highway stretch was recorded below. If the mean of the data is 63.2 with a standard deviation of 6.2, circle all data values with a z-score less than 0.5.

{49, 58, 60, 63, 64, 64, 65, 67, 70, 72}

Answer 1

Data values: 63, 64, 64, 65

Explanation:

`Z=(x-\mu)/(T)\ or\ Z=(\mu-x)/(T)`

a.

`0.5 = (x-63.2)/(6.2)`

x - 63.2 = 0.5 × 6.2

x = 66.3

b.

`0.5 = (63.2-x)/(6.2)`

63.2 - x = 0.5 × 6.2

x = 60.1

values that falls within 60.1 < x < 66.3

= 63, 64, 64, 65