# Time to Practice – Week One

Some questions in Part A require that you
access data from Statistics for People Who (Think
They) Hate Statistics. This data is available on the student website under

1.
By hand, compute the
mean, median, and mode for the following set of 40 reading scores:

SUMMARY

 31 32 43 42 24 34 25 44 23 43 24 36 25 41 23 28 14 21 24 17 25 23 44 21 13 26 23 32 12 26 14 42 14 31 52 12 23 42 32 34

2.
Compute the means for the
following set of scores saved as Ch. 2 Data Set 3 using IBM®SPSS® software. Print out a copy of the output.

 Hospital size (number of beds) Infection rate (per 1,000 admissions) 234 1.7 214 2.4 165 3.1 436 5.6 432 4.9 342 5.3 276 5.6 187 1.2 512 3.3 553 4.1

3.
You are the manager of a
fast food store. Part of your job is to report which special is selling best to
the boss at the end of each day. Use your knowledge of descriptive statistics
and write one paragraph to let the boss know what happened today. Use the
following data. Do not use IBM®SPSS®software to compute the statistics needed; rather, do
it by hand. Include a copy of your work.

 Special number Sold Cost Huge Burger 20 \$2.95 Baby Burger 18 \$1.49 Chicken Littles 25 \$3.50 Porker Burger 19 \$2.95 Yummy Burger 17 \$1.99 Coney Dog 20 \$1.99 Total specials sold 119

4.
Suppose you are working
with a data set that has some different (much larger or much smaller than the
rest of the data) scores. What measure of central tendency would you use and
why?

5.
For the following set of
scores, compute the range, the unbiased and the biased standard deviations, and
the variance. Do the exercise by hand.

31, 42, 35, 55, 54, 34, 25, 44, 35

Why is the unbiased
estimate greater than the biased estimate?

6.
Use IBM®SPSS®software to compute all the
descriptive statistics for the following set of three test scores over the
course of a semester. Which test had the highest average score? Which test had
the smallest amount of variability?

 Test 1 Test 2 Test 3 50 50 49 48 49 47 51 51 51 46 46 55 49 48 55 48 53 45 49 49 47 49 52 45 50 48 46 50 55 53

7.
This practice problem uses
the data contained in the file named Ch. 3 Data Set 3. There are two variables
in this data set.

 Variable Definition Height Height in inches Weight Weight in pounds

Using IBM®SPSS®software, compute all of the
measures of variability you can for height and weight.

8.
Review the following
frequency distribution. Create a histogram either by hand or by using some
other application such as a Microsoft®Excel®document.

 Class interval Frequency 90–100 12 80–89 14 70–79 20 60–69 24 50–59 28 40–49 29 30–39 21 20–29 15 10–19 17 0–9 12

9.
looking to improve her students’ level of engagement during group discussions
and instruction. She keeps track of each of the 15 third graders’ number of
responses every day for 1 week. This information is available in Ch. 4 Data Set
2. Use IBM®SPSS®software to create a bar chart (one bar for each day).

10.
Identify whether these
distributions are negatively skewed, positively skewed, or not skewed at all,
and why.

a.
This talented group of
athletes scored very high on the vertical jump task.

b.
On this incredibly crummy
test, everyone received the same score.

c.
On the most difficult
spelling test of the year, the third graders wept as the scores were delivered.

11.
For each of the following,
indicate whether you would use a pie, line, or bar chart, and why.

a.
The proportion of freshmen,
sophomores, juniors, and seniors in a particular university

b.
Change in GPA over four
semesters

c.
Number of applicants for
four different jobs

d.
Reaction time to different
stimuli

e.
Number of scores in each of
10 categories