Question

Easter candy expenditure per consumer is normally distributed with a standard deviation of $2.51. A candy manufacturer claims that the average Easter candy expenditure per consumer is no more than $20. Fifteen consumers were randomly selected. The average Easter candy expenditure per consumer was found to be $21.22 with a standard deviation of $3.00. Can you reject the candy manufacturer's claim at α=.05?

What is the 99% confidence interval for the true average Easter candy expenditure per consumer (in $)?

	a.	None of the answers is correct
	b.	(19.5512, 22.8888)
	c.	(18.9140, 23.5260)
	d.	(19.9498, 22.4902)
	e.	(20.1539, 22.2861)

Answer 1

We have given that,              
              
Sample mean =$21.22      
Population standard deviation=$2.51  
Sample size=15      
Level of significance =0.01      
Z critical value (by using Z table)=2.576      
              
Confidence interval formula is              


=(19.551,22.889)

b.	(19.5512, 22.8888)