A) Standard error (SE) = standard deviation / square root of sample size
SE = 15 / sqrt(36)
SE = 2.5
B) To find the probability of a customer being more than 31 years old, we need to convert this value to a z-score using the formula:
z = (x - mean) / standard error
z = (31 - 37.5) / 2.5
z = -2.6
Using a z-score table or calculator, we can find that the probability of a z-score being less than -2.6 is 0.0047. Therefore, the probability of the next customer being more than 31 years old is approximately 1 - 0.0047 = 0.9953 (or 99.53%).
C) To find the probability of a customer being less than 42 years old, we again need to convert this value to a z-score:
z = (42 - 37.5) / 2.5
z = 1.8
Using a z-score table or calculator, we can find that the probability of a z-score being less than 1.8 is 0.9641. Therefore, the probability of the next customer being less than 42 years old is 0.9641 (or 96.41%).
The age of customers for a particular retail store follows a normal distribution with a mean of 37.5 years and standard deviation of 15 years given the sample size is 36
A compute standard error?
B what is the probability that the next customer who enters the store will be more than 31 years old?
C what is the probability that the next customer who enters the store will be less than 42 years old?
1 answer