Numerical Measurement
Geometric mean is a measure of
location
The measure of location which is the most likely to be influenced by extreme values in the data set is the
mean
Each individual outcome of an experiment is called
a sample point
A numerical description of the outcome of an experiment is called a
random variable
What is defined by numerical characteristics of a population?
Parameters
The variance of a sample of 169 observations equals 576. The standard deviation of the sample equals
24
The 50th percentile is the
a.mode.
b.median.
c. mean.
d. third quartile.
b. median
A measure of the average value of a random variable is called a(n)
a.variance.
b.standard deviation.
c.expected value.
d.coefficient of variation.
c.expected value.
A probability distribution showing the probability of x successes in n trials, where the probability of success does not change from trial to trial, is termed a
binomial probability distribution
From a group of 12 students, we want to select a random sample of 4 students to serve on a university committee. How many combination of random samples of 4 students can be selected?
495
The hourly wages of a sample of 130 system analysts are given below.
mean = 60
range = 20
mode = 73
variance = 324
median = 74
30%
The following data show the yearly salaries of football coaches at some state supported universities.
Salary University (in $1,000)
A 53
B 44
C 68
D 47
E 62
F 59
G 53
H 94
For the above sample, determine the following measures.
a.The mean yearly salary
b.The standard deviation
c.The mode
d.The median
a. 60
b. 15.8
c. 53
d. 56
Two of the cylinders in an eight-cylinder car are defective and need to be replaced. If two cylinders are selected at random, what is the probability that
a.both defective cylinders are selected?
b.no defective cylinder is selected?
c.at least one defective cylinder is selected?
a. 2/56
b. 30/56
c. 26/56
The probability distribution of the daily demand for a product is shown below.
Demand Probability
0 0.05
1 0.10
2 0.15
3 0.35
4 0.20
5 0.10
6 0.05
What is the expected number of units demanded per day?
Determine the variance and the standard deviation.
a. 3.05
b. variance = 2.0475
std. dev. = 1.431
A simple random sample of 100 observations was taken from a large population. The sample mean and the standard deviation were determined to be 80 and 12 respectively. The standard error of the mean is
1.20
Forty percent of the students who enroll in a statistics course go to the statistics laboratory on a regular basis. Past data indicates that 65% of those students who use the lab on a regular basis make a grade of A in the course. On the other hand, only 10% of students who do not go to the lab on a regular basis make a grade of A. If a particular student made an A, determine the probability that she or he used the lab on a regular basis.
0.8125
A production process produces 90% non-defective parts. A sample of 10 parts from the production process is selected.
a. What is the probability that the sample will contain 7 non-defective parts?
b. What is the probability that the sample will contain at least 4 defective parts?
c. What is the probability that the sample will contain less than 5 non-defective parts?
d. What is the probability that the sample will contain no defective parts?
a. 0.0574
b. 0.0128
c. 0.0001
d. 0.3487
A simple random sample of 6 recent graduates revealed the following information about their weekly incomes.
Graduates Weekly Income
A $250
B $270
C $285
D $240
E $255
F $290
a.What is the expected value of the average weekly income of all the recent graduates?
b.What is the expected value of the standard deviation for the population?
a. $265
b. $20
In the two upcoming basketball games, the probability that UTC will defeat Marshall is 0.63, and the probability that UTC will defeat Furman is 0.55. The probability that UTC will defeat both opponents is 0.3465.
a.What is the probability that UTC will defeat Furman given that they defeat Marshall?
b.What is the probability that UTC will win at least one of the games?
c.What is the probability of UTC winning both games?
a. 0.55
b. 0.8335
c. 0.3465
Fifty-five percent of the applications received for a particular credit card are accepted. Among the next twelve applications,
a.What is the probability that all will be rejected?
b.What is the probability that all will be accepted?
c.What is the probability that exactly 4 will be accepted?
d.What is the probability that fewer than 3 will be accepted?
e.Determine the expected number and the variance of the accepted applications.
a. 0.0001
b. 0.0008
c. 0.0762
d. 0.0079
e. 6.60; 2.9700
A population of 1,000 students spends an average of $10.50 a day on dinner. The standard deviation of the expenditure is $3. A simple random sample of 64 students is taken.
a. What are the expected value, standard deviation, and shape of the sampling distribution of the sample mean?
b. What is the probability that these 64 students will spend a combined total of more than $715.21?
c. What is the probability that these 64 students will spend a combined total between $703.59 and $728.45?
a.10.5
0.363
normal
b.0.0314
c.0.0794