Question

OFF DO O Homework 1 AutoSave Home E11 Formulas Data Review View Insert . x Page Layout fx Suppose you analyzed the average monthly credit card bill of Visa credit card customers using two randomly selected samples: one with 140 Visa credit card customers (Sample #1) and one with 95 Visa credit card customers (Sample #2). Every credit card customer in Sample #1 had a monthly credit card bill of $1.981. Sample #2, on the other hand, had an average monthly credit card bill of $1,865 with a variance of 1,389,629 ($)^2. If you combined these samples into one... Question 2 What would be the combined monthly credit card bill average (in dollars)? Question 3A What is the combined monthly credit card bill median (in dollars)? Question 3B What is the shape of the combined monthly credit card bill distribution (in dollars)? Question 4 What would be the combined monthly credit card bill standard deviation (in dollars)?

Please show math, not Excel functions or shortcuts.

Important: Make sure you carry all decimals until you reach your answer, then round to four decimals.

Answer 1

2)

average =(140*1981+95*1865)/(140+95)=1934.1064

3A)median =1981 (as more than 50% values are at 1981)

3B) left skewed as mean is less than median

4) here sum of all data values =∑x =(140*1981+95*1865)=454515

sum of square of all data values =∑x² =(140*1981²+(95-1)*177175+95*1865²)=1010467041

total sample size n=140+95 =235

therefore standard deviation =sqrt((∑x² -(∑x )²/n)/( n-1))=749.3207