Abank wishes to estimate the mean credit card balance owed by its customers. the population standard deviation is estimated to be $300. if a 98 percent confidence interval is used and an interval of $78 is desired, how many customers should be sampled? a. 725b. 80c. 57d. 320

B. 80

Step-by-step explanation:

We know that the formula to find the sample size is given by :-

, where = population standard deviation.

E= margin of error

z*= Two -tailed critical z-value

Given : Confidence level = 98% =0.98

Population standard deviation :

Also, from z-table for (two tailed ), the critical will be =

Then, the required sample size must be :

 [To the nearest option]

Hence, the required sample size = 80

Hence, the correct option is option B. 80

4sqrt5

step-by-step explanation:

the base has dimensions of 8 x 4, so the diagonal is 64 + 16 square rooted or 4sqrt5.