Vavuniya Campus of the University of Jaffna Department of Physical Science Answer all questions Selection Exam for Quiz Competition Time: 30 minutes Underline the correct answer 1. Which of these is an example of a categorical variable? a) flavor of soft drink ordered by each customer at a fast food restaurant b) height, measured in inches, for each student in a class c) points scored by each player on a team 2. Numerical and pictorial information about variables are called a) analytical statistics b) descriptive statistics c) inferential statistics 3. The entire group of interest for a statistical conclusion is called the a) data b) population c) sample 4. A subgroup that is representative of a population is called a) a category b) data c) a sample 5. Two types of statistical variables are a) categorical and descriptive b) categorical and numerical c) descriptive and numerical 6. Which is best for categorical variables? a) bar chart b) box and whisker plot c) stem and leaf plot d) scatterplot 7. Which is best for numerical variables? a) bar chart b) pie chart c) stem and leaf plot 8. Which plot does not display all of the values of the data? a) box and whisker plot b) dot plot c) Stem and leaf plot 9. Which shows the quartiles and median most clearly? a) box and whisker plot b) histogram c) stem and leaf plot 1
10.
Which of the following statements are true? I. Categorical variables are the same as qualitative variables. II. Categorical variables are the same as quantitative variables. III. Quantitative variables can be continuous variables. a) b) c) d)
11.
I only II only I and II I and III
Which of the following is a discrete random variable? I. The average height of a randomly selected group of boys. II. The annual number of sweepstakes winners from New York City. III. The number of presidential elections in the 20th century. a) b) c) d)
I only II only I and II I and III
12.
What is the median of the following set of numbers? {12, 8, 13, 4, 7, 6, 3, 3, 15} a) 12 b) 8 c) 7 d) 7.5
13.
What is the range of the following set of data? {2, 5, 2, 8, 45, 8, 17, 9, 16} a) 43 b) 45 c) 15 d) None of the above
14.
Consider the 3 observations 3,7,11 for which mean is 7 and the standard deviation is 4. If we add 2 to each value, what are the new mean and standard deviation? a) The mean is 9 and the standard deviation is 2. b) The mean is 9 and the standard deviation is 4. c) The mean is 7 and the standard deviation is 4. d) The mean is 7 and the standard deviation is 6. e) None of the above.
2
Use the box plot below showing the ages of the contestants in a singing competition for questions 15 and 16.
15.
What is the median? a) 13 b) 15 c) 19 d) 18
16.
What is the inter-quartile range? a) 4 b) 6 c) 14 d) 8
17.
Four friends take an IQ test. Their scores are 96, 100, 106, 114. Which of the following statements is true? I. II. III. IV. a) b) c) d) e)
The mean is 103. The mean is 104. The median is 100. The median is 106.
I only II only III only IV only None is true
3
18.
The dot-plot below shows the number of televisions owned by each family on a city block. * * * * * * * * * * * * * * * * * * * * * 0 1 2 3 4 5 6 7 8 Which of the following statements are true? a. b. c. d. e.
19.
The distribution is right-skewed with no outliers. The distribution is right-skewed with one outlier. The distribution is left-skewed with no outliers. The distribution is left-skewed with one outlier. The distribution is symmetric.
Consider the histograms below.
Which of the following statements are true? I. Both data sets are symmetric. II. Both data sets have the same range. a. I only b. II only c. I and II d. Neither is true. e. There is insufficient information to answer this question. 20.
Consider the boxplot below.
2 4 6 8 10 12 14 Which of the following statements are true? I. The distribution is skewed right. II. The interquartile range is about 8. III. The median is about 10. a. I only b. II only c. III only d. I and III e. II and III
4
16
18
21.
Below, the cumulative frequency plot shows height (in inches) of college basketball players.
What is the interquartile range? a. b. c. d. e.
3 inches 6 inches 25 inches 50 inches None of the above
22.
One marble jar has several different colored marbles inside of it. It has 1 red, 2 green, 4 blue, and 8 yellow marbles. All the marbles are the same size and shape. If Peter takes out a marble from the jar without looking, what is the probability that he will NOT choose a yellow marble? a) 8/15 b) 7/15 c) 7/8 d) 8/7
23.
A coin is tossed three times. What is the probability that it lands on heads exactly one time? a. b. c. d. e.
24.
0.125 0.250 0.333 0.375 0.500
Which of the following statements are true? I. The mean of a population is denoted by ̅ . II. Sample size is never bigger than population size. III. The population mean is a statistic. a) b) c) d) e)
25.
I only. II only. III only. All of the above. None of the above.
X is a random normal variable, with mean µ and variance
. The standardize form of X is
. What are the mean and variance, respectively of Z? a) b) c) d)
0, 1 2, 1 1, 0 2, 0 5
