STAT 512 solution correct answers

STAT 512 solution correct answers

1.  A survey of the number of calls received by a sample of Southern Phone Company subscribers last week revealed the following information.

52, 43, 30, 38, 30, 42, 12, 46, 39, 37, 34, 46, 32, 18, 41, 5

a)  Develop a stem-and-leaf chart. Note: A typical row for the Stem & Leaf plot might look like 3ê0269. Where, the vertical line is obtained by using “Shift & |\” key. The line is inserted at the location of the cursor.

b)      What basic conclusions can be drawn from this chart?

c)      Compute the 5 number System for this data set and list Xmin, Q1, Q2, Q3 & Xmax. See Videos “5_Number_Sysytem” in Videos –Topics In Stat 230.

2. The chart below gives the percentage of counties in the US that use various methods for recording votes in 1980 & 2002. Set up side-by-side bar charts by year using the instruction for Side-By-Side Charts in the Class Notes Conference.   Copy/Paste your Chart into the TFE Editor from EXCEL.

METHOD

1980

2002

Punch cards

18.5

15.5

Lever machines

36.7

10.6

Paper ballots

40.7

10.5

Optical scan

0.8

43.0

Electronic

0.2

16.3

Mixed

3.1

4.1

3. The following are a sample of the weights of nine jars of peanut butter.

             7.69, 7.72, 7.80, 7.86, 7.90, 7.94, 7.97, 8.06, 8.09

a) Compute the median weight.

b) Compute the standard deviation of the sample using the shortcut formula. Show the formula and values for each term and compute the answer.  Use the TFE Equation Editor.

c)  Compute the 5 Number System for this data.  Just list the values as Xmin=xxx, Q1=xxx,Q2=xxxx,Q3=xxxxx, Xmax = xxxx.

d) Are there outliers? An outlier value is defined as unusually large or small according to the expressions: Answer yes or no.

                           Outlier > Q3 + 1.5(Q3-Q1) or,

                           Outlier < Q1-1.5(Q3-Q1)

4.  Answer questions a. through f. of 3.23 below.

NOTE: The Bienayme-Chebyshev Rule is the same as the Chebyshev’s Rule in Table 2.6 of your text.

5.  Compute the mean and standard deviation for the data in the table below. State your assumptions and show all calculations.

Distance

Frequency

0 to 5

5 to 10

10 to 15

15 to 20

20 to 25

4

15

27

18

6

6.   A box contains 3 red balls and 4 green balls.  If two balls are randomly selected in sequence, without replacement, what is the possibility that a red ball and a green ball are picked out of the box.  State the rule for P(A&B) and then substitute the values and compute the answer.