LGHS Math III Unit 1 mid-unit Test Review
Inferences & Conclusions from Data
Name:_____________________
August 22, 2014
1.
Which survey question is unbiased?
 Do people who vote for John Smith think he is qualified?
 Is it possible to be totally honest in today’s world?
 Is it really important to do homework?
 Do you watch “The Big Bang Theory” at least once a month?
2.
To learn more about employee’s views, 12 workers were randomly selected from each of the
nursing staff, doctors, maintenance staff, cleaning staff, and administrative staff. Which sampling
method was used to create this sample?
(simple random, systematic, stratified random, cluster)
3.
In a school students were assigned a number. A random number was selected and then that student
and every 10th student was surveyed. Which type of sampling was used to find this sample?
4.
Which sampling method below is cluster sampling?
 Out of a meeting of 1000 people, 50 in randomly surveyed.
 Students at a school were grouped by birth month, and then all students born in two randomly
selected months were surveyed.
 A list of subscribers to a magazine were surveyed by using a random number to select the first,
and then every 200th subscriber.
 Radio listeners were instructed to call in and vote for their favorite team.
5.
Find the mean and standard deviation for the following grades?
75, 82, 91, 79, 82, 95, 86, 78
6.
The average rent of a one bedroom apartment in Atlanta is $850 a month and the standard deviation
is $100. Assuming the rents form a normal distribution, what percent of the apartments rent for less
than 800?
7.
According to the empirical rule for normal distributions, approximately what percent of data lies
within one standard deviation (_______), two standard deviations (_______), and three standard
deviations (_____ ) of the mean?
8.
Find the probability P(20.5<X<41.0), on a normal distribution with a mean of 35.3 and a standard
deviation of 5.0.
9.
The heights of American men aged 18 to 24 are approximately normally distributed with mean 68
inches and standard deviation 2.5 inches. Half of all young men are shorter than what value?
10.
If the heights of 99.7% of American men are between 5'0" and 7'0", what is your estimate of the
standard deviation of the height of American men?
11.
Define
𝜎-
z-score -
𝜇-
interspatial time continuum -
Σ-
LGHS Math III Unit 1 mid-unit Test Review
Inferences & Conclusions from Data
Name:_____________________
August 22, 2014
12.
Assuming a normal distribution which data set has the widest range?
𝜇 = 0, 𝜎 = 15
𝜇 = 20, 𝜎 = 27
𝜇 = 15, 𝜎 = 14
𝜇 = 50, 𝜎 = 21
13.
A company produces packets of soap powder labeled "Giant Size 32 Ounces." The actual weight of
soap powder in a box has a normal distribution with a mean of 33 oz. and a standard deviation of
0.8 oz. What proportion of packets are underweight (i.e., weigh less than 32 oz.)? Show all work,
and sketch and shade the normal curve.
14.
Define:
a. Treatments
g. standard deviation
b. Mean
h. response variable
c. stratified random sample
i. explanatory variable
d. cluster sample
j. random sample
e. bias
k. lurking or confounding variable
f. systematic sample
l.
experimental units
15.
The owner of XYZ Greenhouse wants to find out what is the optimum # of hours in the sun for his
daisy gardenia plants. He has 25 plants, and will test them in groups by the number of hours they
get per day (2 hours, 4 hours, 6 hours, 8 hours, and 10 hours). After one week, he will measure the
plant heights.
a. What are the experimental units of study?
b. What is the explanatory variable?
c. What is the treatment?
d. What is the response variable?
e. Draw a diagram to outline the design of the study.
16.
The Rules of Golf state that the diameter of a "conforming" golf ball cannot be any smaller than
1.68 inches. A leading golf ball manufacturer annually produces 3.6 million golf balls with a mean
diameter of 1.75 inches with a standard deviation of .055 inches. Assume a normal distribution.
a. What percentage of golf balls will need to be discarded and not sold to golf equipment
suppliers?
b. The manufacturer spends $381,000 to improve the production process lowers the standard
deviation to .04 inches. How many golf balls can now be sold per year?