56 21 38 17 15 67 45 48 60 56 22 53 37 17
50 92 39 16 59 73 17 31 28 51 74 42 31
What is the arithmetic mean for these observations? (Round the
calculation to two decimal places.)
d. None of the above
2. Using the array in #1 above, calculate the median of the
distribution, rounding to two decimal places.
d. None of the above
3. Using the array in question 1 above, calculate the arithmetic mean
with the single most extreme outlier removed. Round the
calculation to two decimal places.
4. The following is a five-number summary calculated from
observations of the percentage of calories that come from fat in 23
items advertised as "reduced" fat from a sample of fast food chain
restaurants. Form the box-and-whisker plot, select the phrase
below which bests describes the shape of the distribution.
| 15 | 20 | 22 | 26 | 30 |
|____ |______ |______ |_______|_______|
a. Skewed slightly to the left
b. Skewed slightly to the right
c. Symmetrical distribution
d. There is not enough information given to determine the shape
5.62 16.25 11.46 8.45 5.41 11.62 7.5 4.42 7.58 7.54
5.29 10.92 21.62 8.58 11.42 7.29 7.96 10.5 9.29 8.92
What is the third quartile?
6. What is the standard deviation of the distribution of the
observations in the array shown in question 11 above?
7. What is the coefficient of variation for the observations in the array
shown in question 11 above?
a. 39.97 %
d. 46.94 %
8. The employees of a company were surveyed on questions regarding
their educational background and marital status. Of the 600
employees, 400 had college degrees, 100 were single, and 60 were
single college graduates. The probability that an employee of the
company is married and has a college degree is:
9. An advertising executive is studying TV viewing habits of married
men and women during prime time hours. On the basis of past
viewing records, the executive has determined that during prime
time, husbands are watching TV 60% of the time that their wives
are also watching TV. When the husband is not watching TV, 30%
of the time his wife is watching TV. What is the probability that, if
the wife is watching TV, her husband is also watching TV?
10. Mothers Against Drunk Driving is a very visible group whose main
focus is to educate the public about the harm caused by drunk
drivers. A study was recently done that emphasized the problem we
all face with drinking and driving. Four hundred accidents that
occurred on a Saturday night were analyzed. Two items noted were
the number of vehicles involved and whether alcohol played a role in
the accident. The numbers are shown below:
Number of vehicles Involved
Did alcohol play a role? 1 2 3 Totals
Yes 50 100 20 170
No 25 175 30 230 1
Totals 75 275 50 400
Referring to the table above, what proportion of accidents involved
more than one vehicle?
11. Referring to the table in question 20 above, what proportion of the
non-alcohol related accidents were multiple vehicle accidents?
12. A company has 2 machines that produce widgets. An older machine
produces 23% defective widgets, while the new machine produces
only 8% defective widgets. In addition, the new machine produces 3
times as many widgets as the older machine does. What is the
probability that a randomly chosen widget produced by the company
13. A survey is taken among customers of a fast-food restaurant to
determine preference for hamburger or chicken. Of 200 respondents
selected, 75 were children and 125 were adults. 120 preferred
hamburger and 80 preferred chicken. 55 of the children preferred
hamburger. What is the probability that a randomly selected
individual is an adult?
d. None of the above
Thirteen Statistics problems involving Distributions, Probability, Means, Quartiles and Five Number Summary are solved. The solution is detailed and well presented. The response received a rating of "5" from the student who originally posted the question.
Descriptive statistics for cross-sectional data: term project
Deliverable 1: Descriptive Statistics
(10 points) Our main emphasis in the course is "inferential" statistics which means taking samples and drawing an inference or conclusions about the population.
Access raw data or a database from government, business, health, and similar official Web sites pertaining to your area of interest. Collect at least 30 pieces of numerical (quantitative) metric data (see p.15) but no more than an n of 50 (30-50 observations and only one theme). If you have a sample larger than 50 randomly select a subset so your n (sample size) is no more than 50. Explain where these data came from and why they are of interest to you.
Describe the population and the variable. From the data, plot a histogram, a stem-and-leaf diagram and an ogive (polygon). Also calculate the mean, median, mode, range, standard deviation, and quartiles of the data. Create a boxplot. Explain what this analysis tells you.
In a separate appendix (or spreadsheet), list all 30-50 observations labeled from 1 to 30 (up to 50 if n=50) so I can duplicate your work if necessary.
Since you will be doing a histogram you will need to select a sample that consists of numerical (quantitative) data not categorical (qualitative) data (see p.15). A bar graph is not the same as a histogram so in Excel, click bars (right click properties) /format data series/options/gap width (should equal to zero) and this should get rid of the gaps (histograms do not contain gaps...only bar graphs are used for categorical data. Your textbook describes other methods to provide an acceptable histogram and other graphics. If you have a category/class in the data with zero observations then try to get rid of the gap by extending the width of the class interval or at the very least explain it in your comments. Histograms and other descriptive statistics should not add to the confusion or generate more questions but should answer and explain the data. Look at your descriptive statistics and ask if there are any questions that would be asked and can you answer them by modifying the descriptive statistics or adding a comment or label. See also p. 81, exhibits 2.1 and 2.2.View Full Posting Details