A study has indicated that the sample size necessary to estimate the average electricity use by residential customers of a large western utility company is 900 customers. Assuming that the margin of error associated with the estimate will be ±30 watts and the confidence level is stated to be 90 percent, what was the value for the population standard deviation?

Step-by-step explanation:

-The margin of error is calculated using the formula:

-We substitute the values, n=900 and ME=30 in the formula to solve for standard deviation:

Hence, the population standard deviation is 547.1125

the answer would be a 24

step-by-step explanation:

c=2πr=2·π·3=24

1 mph

step-by-step explanation:

if the question is asking how much does she drive per mile then,

13 / 13 = 1 mph