Calculate Statistics

STAT 3309 FALL 2017

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HOMEWORK #3

The insurance agent at Central Insurance Company wishes to analyze

the number of minutes that the company’s secretary spends on the phone

with customers inquiring about insurance rates. The times for 36

randomly selected calls are given.

8.8 5.7 6.4 6.5 12.9 8.9 7.0 11.1 5.1

3.6 4.8 11.9 3.9 2.4 12.7 6.3 6.5 12.1

8.2 13.5 5.4 9.7 13.6 5.9 11.9 4.9 11.8

6.1 2.7 8.8 11.9 12.4 19.3 5.7 5.6 7.5

NOTE: * Unless directions indicate otherwise, do not recalculate anything by hand

that has already been calculated by EXCEL! Use values on the output, that

is why we are using the computer & not doing calculations by hand.

* Perform any calculations in the most efficient way possible.

* Interpretations should contain no statistical jargon, and should be related

to the data set (don’t forget the units of measure!)

PRINT OUT ANOTHER COPY OF YOUR EXCEL OUTPUT (INCLUDING THE HISTOGRAM)

WITH ANY NECESSARY CORRECTIONS TO YOUR OUTPUT FROM HW1 and/or HW2

Again, staple sheets together and do not write on the back of any page.

Round to the nearest ten thousandth (4 decimal places) during calculations.

Your final answers must also be given to the nearest ten thousandth.

FOLLOW DIRECTIONS AND SHOW YOUR WORK WHEN REQUIRED!!

DO NOT TURN IN THIS PAGE

CONTINUED ON NEXT PAGE…

STAT 3309 NAME(s)_________________________

FALL 2017 HW3 (55pts) _________________________

CLASS DAYS_________ TIME________

You will turn in these 3 pages (with questions answered) and one new copy

of your EXCEL OUTPUT (from HW1 and including the histogram) attached.

Please staple in the upper left hand corner.

Answer (neatly) the following:

1. (9pts) Find (do not calculate) the following on your EXCEL output

and list (4 decimal places) the values below:

n = _____________ s = ______________

x = _____________ 50th percentile = ______________

2. (3pts) Calculate the 70 th percentile. SHOW ALL YOUR WORK!!!!!

ANSWER:___________

3. Mr. Herz spent 6.3 minutes inquiring about insurance rates with the

secretary at Central Insurance Company. What is the Z-score for his

call? (SHOW ALL YOUR WORK FOR CREDIT!!) (5pts)

Z = ____________

INTERPRET THE Z-SCORE BY FILLING IN THE BLANKS (4pts)

The length of Mr. Herz’s call is ______ standard deviations

___________ the customer __________.

4. a) (6pts) Using values you gave in question #1, calculate

ksx  for 2,1k SHOW YOUR WORK under each answer for full credit!!

sx  = ____________ sx  = ____________

sx 2 = ____________ sx 2 = ____________

b) What is the actual percentage of data values

that lie within one standard deviation of the mean? ________ (2pts) SHOW YOUR WORK!!

c) What statement can you make about the sample of inquiry times

using Chebyshev’s Rule?  2k State in context (relate your answer to the data set) and no

statistical jargon!

5. Calculate the first quartile. ANSWER: ______________ (3pts)

SHOW YOUR WORK!!

6. Interpret the first quartile in context. (4pts)

7. (5pts)

Is 19.3 an outlier? ________ (yes or no?)

Explain why or why not.

YOU MUST GIVE A CLEAR EXPLANATION AND SHOW ALL YOUR WORK!!!

8. (4pts) Can you use the Empirical Rule in this case? _____________(yes or no?)

Why? (circle your answer)

A. Because of my results in question 4.

B. Because of my result in question 7.

C. Because of the shape of the histogram.

D. All of the above.