Question

A dentist is interested in obtaining information about delinquent (past due) accounts. Since the practice opened 5 years ago, delinquent accounts are normally distributed with an average of 58 days and a variance of 169.00 days. The dentist randomly selected a sample of 32 delinquent accounts with an average of 47 days. a) The dentist wants to know what average number of days is more than 61% from the past 5 years. b-Is the average days from the sample of 32 less than the 61% average from the past 5 years? Yes, No or NA

Answer 1

a)

Let the x = average number of days equal to 61% from the past 5 years

The z score for probability 0.61 is obtained from the standard normal distribution table,

Average 62 number of days is more than 61% from the past 5 years.

b)

The average number of days from the sample of 32 is 47 days which is less than 62 days hence we can say that average days from the sample of 32 is less than the 61% average from the past 5 years