A dentist is interested in obtaining information about delinquent (past due) accounts. Since the practice opened 8 years ago, delinquent accounts are normally distributed with an average of 43 days and a variance of 196.00 days. The dentist randomly selected a sample of 20 delinquent accounts with an average of 47 days.

Respuesta :

Answer:

The average number of days is more than 43% from the past 8 years is 43.15 days and it is less than Sample mean of 47 for 20 samples

Explanation:

From the data

Population mean = μ=43 days

Population variance=[tex]\sigma^2[/tex]=196

                                  [tex]\sigma=\sqrt{196}=14[/tex]

Sample size n=20

Sample mean [tex]\bar{x}[/tex]=47

Part a:

Using values from the reference question found online.

Given α=43%

α=0.43

At 1-α=0.57

[tex]z_{\alpha}[/tex] from the table yields 0.18

Now the value is given as

[tex]\bar{x}=\mu+z_{\alpha}\sqrt{\frac{\sigma}{n}}\\\bar{x}=43+0.18\sqrt{\frac{14}{20}}\\\bar{x}=43.15 days[/tex]

Part b:

Sample mean of 47 for 20 samples is more than 43% of the days from last 8 years.

Answer:0.1059

Explanation:

Please see attached a solved copy of the question

Ver imagen samag4real