PLEASE SHOW WORK The National Quality Research Center provides a quarterly measu
ID: 3357015 • Letter: P
Question
PLEASE SHOW WORK
The National Quality Research Center provides a quarterly measure of consumer opinion about product services. A survey of 10 restaurants in the Fast Food/Pizza group showed a sample mean customer satisfaction index of 71. Past data indicate that the population standard deviation of the index has been stable with a value of 5. (a) Compute a 95% interval estimate of customer satisfaction index of restaurants in the Fast Food/Pizza group. Show your steps and manual (hand and calculator) calculations in 4 decimal places, where possible. (b) Interpret your estimate in (a) above. (c) What assumption is required for your estimate above to be valid?Explanation / Answer
we knwo that the confidence interval is given as
Mean +- z*sd/sqrt(n) , here mean = 71 , sd = 5 and n = 10 , also for 95% CI the value of z score from the table is 1.96
putting the values in the equation and solving for plus and minus sign we get
71+- 1.96*5/sqrt(10)
67.9 and 74
This means that we are 95% confident that the true value of the mean of customer satisfaction index would lie in the interval 67.9,74
The data must follow normal distribution for the assumption to be valid