Question

What price do farmers get for the peach crops? in the third week of June, a random sample of 40 farming regions gave a sample mean of $6.88 per basket. assume that the standard deviation is known to be $1.92 per basket. find a 90% confidence interval for the population mean price per basket that farmers in this region get for their peach crop.

Answer 1

Given:
n = 40, sample size
xb = $6.88, sample mean
σ = $1.92, population standard deviation

At 90% confidence interval, the expected range is 
$(xb - 1.645 \frac{ \sigma }{ \sqrt{n}} ,\, xb + 1.645 \frac{ \sigma }{ \sqrt{n} } )$
= [ 6.88 - 1.645*(1.92/√40), 6.88 + 1.645*(1.92/√40)]
= (6.38, 7.38)

Answer:
The 90% confidence interval is ($6.38, $7.38)