Question

A simple random sample of months of sales data provided the following information: Month Units Sold a. Develop a point estimate of the population mean number of units sold per month. b. Develop a point estimate of the population standard deviation (to 2 decimals).

Answer 1

a) X[bar]=93

b)S=5.39

Explanation:

Hello!

A simple random sample of 5 months of sales data provided the following information: Month: 1 2 3 4 5 Units Sold: 94 100 85 94 92

a. Develop a point estimate of the population mean number of units sold per month.

The variable of interest is:

X: Number of sales per month.

A random sample of n=5 months was taken, for each month, the number of units sold was recorded. To calculate the mean of the sample you have to add all the observed frequencies (Units Sold) by the sample size (n)

X[bar]= ∑X/n= 465/5=93

You can say that, on average, 93 units were sold over the 5-month period.

b. Develop a point estimate of the population standard deviation.

To calculate the sample standard deviation you have to calculate the variance and then its square root:

`S^2= (1)/(n-1)[sumX^2-((sumX)^2)/(n) ]`

∑X= 465

∑X²= 43361

`S^2= (1)/(4)[43361-((465)^2)/(5) ]= 29`

S= √29= 5.385≅ 5.39

I hope this helps!