Long Island University

﻿Long Island University

GBA 519 – StatisticsFall 2021

Test 1

1- The classification of student class designation (freshman, sophomore, junior, senior) is an example of a(n)

a. nominal random variable.

b. interval random variable.

c. ordinal random variable.

d. a parameter.

2- All calculations are permitted on what type of data?

a. Interval data

b. Nominal data

c. Ordinal data

d. All of these choices are true.

3- Data

a. is always numeric.

b. is always nonnumeric.

c. is the raw material of statistics.

d. None of the above..

4- The relative frequency of a class in a histogram is computed by

a. dividing the frequency of the class by the number of classes.

b. dividing the frequency of the class by the class width.

c. dividing the frequency of the class by the total of all frequencies.

d. None of these choices.

5- Qualitative data

a. must be numeric.

b. must be nonnumeric.

c. cannot be numeric.

d. may be either numeric or nonnumeric.

6- – Which of the following is most likely a sample as opposed to a population?

All customers of a bank

Students in a given university

Every fifth student to arrive at the book store on your campus

Registered voters in the State of Michigan

7- In a cumulative frequency distribution, the last class will always have a cumulative frequency equal to

a. One.

b. 100%.

c.

d. the total number of elements in the data set.

none of the above.

8- The upper limit of box-plots (the end of the right whisker) is

a. always greater than the largest value in the data set.

b. always smaller than the largest value in the data set.

c. always equal to the largest value in the data set.

d. none of the above.

9- The pie chart is an appropriate chart for

a. numerical data only.

b. ratio scale data only.

c. categorical data.

d. Interval data only.

10- The 60th percentile is a data value that is

a. smaller than the median.

b. between the median and the smallest value in the data set.

c. larger than the median and smaller than the largest value in the data set.

d. larger than the smallest value in the data set and smaller than the median.

(10 Points)

A survey of students was conducted to determine how they rate the quality of on-line classes. Students were asked to rate the overall quality as Excellent (E), Very Good (V), Good (G) and Poor (P). The following data were obtained:

E G G V P P V V E V

P E G G V V P P V E

P V G G G G E V P G

V V V V P P G G E V

a) What percentage of students rated the quality as Very Good?

b) Construct a bar graph of this data and provide required descriptive information for this graph.

2- (15 Points)

The ordered array below resulted from taking a sample of 25 batches of 500 computer chips and determining how many in each batch were defective.

Defects

1244556799121215

17 2021232325262727282929

a) Construct a frequency distribution and a Histogram .

b) Construct a cumulative percentage distribution and graph it (OGIVE).

3 – (15 points)

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid and have no private health insurance. The ages of 20 uninsured senior citizens were as follows:

73628164906668686961

75747663818286876592

a) Identify the median age of the uninsured senior citizens.

b) Determine the 5 number summary for this data.

c) Prepare a box-plot for this data.

d) Is the data skewed? Right or Left?

4- (15 Points)

Find the Z score for the following data and identify the outliers, if any.

20, 26, 24, 19, 39

5- (15 Points)

Consider the following sample:

x 12 7 8 6 6

y 22 16 12 14 10

Prepare the scatter plot.

Calculate the Covariance.

Calculate the coefficient of correlation and comment on the relationship between x and y.

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