It cost Naomi $7.70 to send 154 text messages how many text messages did she send if she spent $5.25
1 answer:
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Answer: (29.35, 40.95)
Step-by-step explanation:
Formula to find the confidence interval for population mean :-
, where = sample mean.
z*= critical z-value
n= sample size.
= Population standard deviation.
As per given , we have
n= 37
Using z-table, the critical z-value for 95% confidence = z* = 1.96
Then, the confidence interval for the population mean will be :
Hence, a 95% confidence interval for the population mean = (29.35, 40.95)