Qnt351 qnt/351qnt 351 week 5 final exam

QNT 351 Week 5 FINAL EXAM
1-What is the variable used to predict the value of another called?
•
Correlation variable
•
Dependent variable
•
Variable of determination
•
Independent variable

2-A dot plot shows
•
the general shape of a distribution
•
the interquartile range
•
the mean, median, and mode
•
the relationship between two variables

3-A small sample of computer operators shows monthly incomes of $1,950, $1,775, $2,060, $1,840, $1,795, $1,890, $1,925, and $1,810. What are these ungrouped numbers called?
•
Class limits
•
Histogram
•
Class frequencies
•
Raw data

4
Twenty randomly selected statistics students were given 15 multiple-choice questions and 15 open-ended questions, all on the same material. The professor was interested in determining on which type of questions the students scored higher. This experiment is an example of
•
a one sample test of means
•
a test of proportions
•
a two sample test of means
•
a paired t-test

The shape of any uniform probability distribution is
•
bell shaped
•
positively skewed
•
rectangular
•
negatively skewed
What is the chart called when the paired data (the dependent and independent variables) are plotted?
•
Scatter diagram
•
Bar chart
•
Histogram
•
Pie chart
7
Suppose we test the difference between two proportions at the 0.05 level of significance. If the computed z is -1.07, what is our decision?
•
Reject the null hypothesis.
•
Take a larger sample.
•
Do not reject the null hypothesis.
•
Reserve judgment.

For a standard normal distribution, what is the probability that z is greater than 1.75?
•
0.0401
•
0.0459
•
0.9599
•
0.4599

If two events A and B are mutually exclusive, what does the special rule of addition state?
•
P(A or B) = P(A) – P(B)
•
P(A and B) = P(A) + P(B)
•
P(A and/or B) = P(A) + P(B)
•
P(A or B) = P(A) + P(B)

The performance of personal and business investments is measured as a percentage, return on investment. What type of variable is return on investment?
•
Continuous
•
Discrete
•
Qualitative
•
Attribute

11
For a hypothesis test comparing two population means, the combined degrees of freedom are 24. Which of the following statements about the two sample sizes is NOT true? Assume the population standard deviations are equal.
•
Sample A = 10; sample B = 16
•
Sample A = 13; sample B = 13
•
Sample A = 11; sample B = 13
•
Sample A = 12; sample B = 14

The test scores for a class of 147 students are computed. What is the location of the test score associated with the third quartile?
•
75%
•
74
•
37
•
111

The names of the positions in a corporation, such as chief operating officer or controller, are examples of what level of measurement?
•
Ordinal
•
Nominal
•
Interval
•
Ratio

The general process of gathering, organizing, summarizing, analyzing, and interpreting data is called
•
descriptive statistics
•
levels of measurement
•
statistics
•
inferential statistics

For any data set, which measures of central location have only one value?
•
Mean and median
•
Mode and mean
•
Mode and standard deviation
•
Mode and median

What is the level of significance?
•
Beta error
•
Probability of a Type II error
•
Probability of a Type I error
•
z-value of 1.96
17
A sample of single persons receiving social security payments revealed these monthly benefits: $826, $699, $1,087, $880, $839, and $965. How many observations are below the median?
•
2
•
3
•
1
•
0

18
The mean of any uniform probability distribution is
•
(b – a)/2
•
nπ
•
Σ x/ η
•
(a + b)/2
19
The National Center for Health Statistics reported that of every 883 deaths in recent years, 24 resulted from an automobile accident, 182 from cancer, and 333 from heart disease. Using the relative frequency approach, what is the probability that a particular death is due to an automobile accident?
•
24/883 or 0.027
•
24/333 or 0.072
•
182/883 or 0.206
•
539/883 or 0.61
For the normal distribution, the mean plus and minus 1.96 standard deviations will include about what percent of the observations?
•
99.7%
•
68%
•
50%
•
95%
21
What level of measurement is the number of auto accidents reported in a given month?
•
Ratio
•
Interval
•
Nominal
•
Ordinal
The sum of the deviations of each data value from this measure of central location will always be 0.
•
Standard deviation
•
Mode
•
Mean
•
Median

Monthly commissions of first-year insurance brokers are $1,270, $1,310, $1,680, $1,380, $1,410, $1,570, $1,180, and $1,420. These figures are referred to as
•
raw data
•
frequency distribution
•
a histogram
•
frequency polygon
The main purpose of descriptive statistics is to
•
make inferences about a population
•
summarize data in a useful and informative manner
•
gather or collect data
•
determine if the data adequately represents the population
25
What type of variable is the number of robberies reported in your city?
•
Continuous
•
Discrete
•
Qualitative
•
Attribute
The measurements of weight of 100 units of a product manufactured by two parallel processes have same mean but the standard of process A is 15 while that of B is 7. What can you conclude?
•
Both processes are out of control.
•
The weight of units in process A are grouped closer than in process B.
•
The weight of units in process B are grouped closer than in process A.
•
More data is needed to draw a conclusion.
A listing of all possible outcomes of an experiment and their corresponding probability of occurrence is called a
•
random variable
•
frequency distribution
•
probability distribution
•
subjective probabilit
28
Which of the following conditions must be met to conduct a test for the difference in two sample means?
•
Data must be at least of interval scale.
•
Variances in the two populations must be equal.
•
Populations must be normal.
•
Data must be at least of
Shoe sizes, such as 7B, 10D, and 12EEE, are examples of what level of measurement?
•
Interval
•
Ordinal
•
Ratio
•
Nominal
A null hypothesis makes a claim about a
•
Type II error
•
population parameter
•
sample mean
•
sample statistic