07 Jan Calculate the Mean and

Week 1 discussion

By the due date assigned, submit your answers to the Discussion Area.

For each week’s assignment, find your assigned letter and complete the problems associated with that letter. If your instructor has not assigned you a letter, please use the first letter of your last name. Please post both of the problems assigned to you.

Post responses to at least two other students on two separate days of the week. You can:

Ask a question about your classmate’s solution

Offer help when you see an error

Seek help in completing your own problems

Remember that non-substantive posts such as “Good job!” will not count toward your participation score.

By the end of the week, please review and comment on the answers provided by at least two of your peers.

MAT2058 Discussion Questions

Week 1

Textbook: Triola, M. F. (2014). Elementary statistics technology update (12th ed.). Boston, MA:

Pearson Education.

An electronic version of this book is available in this classroom.

Instructions:

? In the Course Home announcement area there should be a listing with your name and

letter assigned for the discussion questions. If there is not such a list, then find the first

letter of your last name below, and complete the two discussion problems associated

with this letter.

? Please show all of the steps and processes you used to solve each of your problems.

? Remember to do both of the problems assigned and to respond to two of your

classmates’ solutions.

? Please try to respond to two of your classmates who have had very different

problems than yours assigned to them. You should receive more credit for doing

so.

? In responding to the postings of at least two of your classmates, you can

o ask a question about your classmate’s solution(s)

o offer help when you see an error, or

o seek help in completing your own problems.

Remember that non-substantive posts such as “Good job!” will not count toward your

participation score. Again, try to respond to at least two classmates who have problems

assigned that are quite different from yours.

? Please note that the assigned problems vary in difficulty and the list has been randomly

generated for each of the two assigned problems.

Week 1 Discussion Questions

See the first

instruction on the

previous page.

Please submit the two discussion items

* Researchers test two different blood pressure

medicines to determine effectiveness.

Y: total cost of text books and supplies for courses

Z: method of payment used for textbooks and supplies

a. What is the population?

b. What is the sample?

c. Classify the three variables as nominal, ordinal, discrete or

continuous.

G

Describe whether the following study would most

likely be “observational” or “experimental”, and

why it would be so.

* One group is given Stilbesterol, the other

nothing, to see which grows faster.

&

Identify each of the following as examples of

(1) nominal, (2) ordinal, (3) discrete, or (4) continuous variables:

a. A poll of registered voters as to which candidate they support

b. The length of time required for a wound to heal when a new

medicine is being used

c. The number of televisions within a household

d. The distance first-year college women can kick a football

H

USA Today conducted a survey asking readers,

“What is the most hilarious thing that has ever

happened to you en route to or during a

business trip?”

a. What kind of sampling method is this?

b. Are the results likely to be biased? Explain why

or why not.

&

At a recent track event with 22 runners in the U.A.E., Ahmed ran

the mile in 5 minutes, 40 seconds. The average time for this event

in the U.A.E. is about 5:52, where at this event it was 5 minutes, 45

seconds. Based on this, identify:

• the statistic

• the parameter

I

The formula for the variance of a sample is:

If the sample mean equals 15 in a sample of 5 data

values, find 4 other values of x that will make the

variance equal zero.

&

Using the information from the first question what would be the

sum of the deviations from the mean for this sample of 5 values,

and why is this so?

J

Consider the sample 2, 4, 7, 8, 9, 10. Find the

following:

a. mean,

b. median,

c. mode

d. midrange

&

a. What does it mean for a value to be non-negative?

b. Describe the conditions necessary for the variance to have

the value zero

K

Consider the sample 1, 2, 4, 7, 8, 9, 10, 20.

Find the following:

a. mean

&

For the data set in the first problem, 1, 2, 4, 7, 8, 9, 10, 20, find:

a. The 50th percentile

b. The third quartile point

b. median,

c. mode

d. midrange

c. The 33rd percentile

L

Suppose we want to take a poll of the attitudes of

senior citizens in the State of Washington. Using

this example, describe in your own words how you

would go about determining this through:

a. Drawing a random sample

b. Drawing a systematic sample

c. Drawing a convenience sample

&

The “average” is a commonly reported statistic. This single bit of

information can be very informative or very misleading, with the

mean and median being the two most commonly reported.

The mean is a useful measure, but it can be misleading. Describe a

circumstance when the mean is very useful as the average and a

circumstance when the mean is very misleading as the average.

M

Describe whether the following study would most

likely be “observational” or “experimental”, and

why it would be so.

* Mystery shoppers monitor the preferences at a

shopping mall.

&

A candidate for a political office claims that he will win the

election. A poll is conducted, and 35 of 150 voters indicate that

they will vote for the candidate, 100 voters indicate that they will

vote for his opponent, and 15 voters are undecided.

a. What is the population parameter of interest?

b. What is the value of the sample statistic that might be used to

estimate the population parameter?

N

Suppose we are with a real estate agency that has

the following houses listed in a specific geographic

area. $150,000; $146,000; $152,000; $155,000;

$143,000; $157,000; $180,000; $148,000; $154,000;

$146,000; $155,000

Which measure of center would be best used to

advertise the house prices for this area? Also,

please add or subtract one or more of the house

prices so that one of the other measures is best, and

state why that measure is better.

&

NV Energy now uses wireless electricity meters to record the

habits of their local electricity users in a certain area, and the data

from those meters will be used to determine energy needs for

next year. What type of observational study (cross-sectional,

retrospective, prospective) this would be, and why?

O

Describe whether the following study would most

likely be “observational” or “experimental”, and

why it would be so.

* Babies were monitored in the nursery for varying

hunger patterns.

&

A set of 50 data values has a mean of 15 and a variance of 36. Find

the standard score of a data value = 21

P

Sixteen randomly selected college students were

asked to state the number of hours they slept the

previous night. The resulting data values are

5,6,6,8,7,7,9,5,4,8,15,6,7,8,7,3

Find the median, mode and midrange of these data.

&

Based on a survey of more than 125,000 people, the National

Center for Health Statistics reported that married people tend to

be healthier than other groups. Among other things, the study

looked at the number of people reporting they were in only fair or

poor health. The study reported the following findings for all

adults aged 18 and older: 11.9% reported they were in fair or poor

health, including 10.5% of the married people, 19.6% of widows,

16.7% of divorced or separated, 12.5% of those never married, and

14% of those living with an unmarried partner. Source: Finger

Lakes Times, December 19, 2004

a. What is the population?

b. What is the sample?

Q

The average weight of all newborn babies at

Dearborn Hospital was estimated by using the

average weight of babies born in the month of April.

Based on this information, identify:

a. A statistic

b. A variable

c. A data value

&

In the autumn of 2003, the National Safe Kids Campaign

conducted a study of helmet use among children ages 5 to 14

who participate in wheeled sports. Data were collected from

various sites across the United States that were designated as

places where children often engage in wheeled sports. Activity,

apparent gender and estimated age were recorded for each rider,

along with information on helmet use. It was found that, overall,

41% of children were wearing a helmet while participating in a

wheeled sport.

a. Was this experimental or observational?

b. Identify the parameter of interest.

c. Identify the statistic and give its value.

R

The average time before hitting a jackpot at the

local casino was estimated by using the average

time that it took the first 100 players. Based on this

information, identify:

a. The population

b. The sample

c. A parameter

&

The mean is a useful measure but it can be misleading.

Describe a circumstance when the mean is a very useful measure

and a circumstance when it is misleading.

S

Would you suspect that the IDEA surveys sent to

South students each term could be biased in the

responses received? Why or why not?

&

Using the data set below, please calculate the:

12 16 12 10 20 10 10

– Mean =

– Median =

– Mode =

T

Consider the sample 2, 4, 7, 8, 9, 10. Find the

following:

a. mean,

b. range

c. midrange

&

Fenton Research has studied the most recent auto accidents in the

State of Arizona, and found that the cause of over 40% of the

accidents was texting while driving. What type of observational

study (cross-sectional, retrospective, prospective) this would be,

and why?

U

Suppose we want to estimate which candidate will

win an election in a large city. Using this example,

describe in your own words how you would go

about determining this through:

a. Drawing a random sample

b. Drawing a systematic sample

c. Drawing a convenience sample

&

The “average” is a commonly reported statistic. This single bit of

information can be very informative or very misleading, with the

mean and median being the two most commonly reported.

The median is a useful measure, but it can be misleading.

Describe a circumstance when the median is very useful as the

average and a circumstance when the median is very misleading

as the average.

V

Using the data set below, please calculate the:

3 12 9 7.5 15 7.5 9

– Mean

– Median

– Mode

A) What does it mean for a value to be non-negative?

B) Describe the conditions necessary for a standard deviation

to have the value zero

W

A cereal manufacturer seeks to test their newest

product against a competitor’s. A group of 100

children was asked to evaluate each brand, and then

to express a preference. To guard against bias,

neither the children, nor the technicians serving

them, were aware of the order in which they were

fed each brand.

A. What is the population?

B. What is the sample?

C. Is the study observational or experimental? Justify

your answer.

&

You have been asked to do a survey of student satisfaction

with MyMathLab courses at South University. Describe how

you would obtain a sample of these types: stratified and

simple random.

X

The average sale price for all houses at U Sell Mine

Realty was estimated by using the average sale price

of 35 randomly selected house sales at the realty.

Based on this information, identify:

a. A statistic

b. A variable

c. A data value

&

The data value x=34 has a deviation (from the mean) value of

16. Explain the meaning of this and what the mean would be

equal to.

Y

Describe whether the following study would most

likely be “observational” or “experimental”, and

why it would be so.

* The nurses on the 5th floor record the medicines

administered every day and report results to the

doctors.

&

You are responsible for planning the parking needed for a new

256-unit apartment complex, and you are told to base the

needs on the statistic “average number of vehicles per

household is 1.9.”

Which average (mean, median, mode) would be best if:

• You wanted to be assured that every unit would have two

parking spots?

Z

The local real estate reported a sampling of house

prices in a certain area as: $56,000; $78,000;

$64,000; $190,000; $60,000; $74,000; $56,000.

What would be the best, most realistic house price

to report, and why?

? the Mean

? the Median

&

For the series of values 12, 15, 17, 22, 24:

? Calculate the Mean and show what the deviations from the

Mean would look like.

? the Mode