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Stevens-Introduction to Statistics, Think & Do 4/e (Homework)

James Finch

Statistics, section 2, Fall 2019

Instructor: Dr. Friendly

Current Score : 30 / 40

Due : Sunday, January 27, 2030 23:30 EST

Last Saved : n/a Saving...  ()

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Question
Points
1 2 3 4 5 6 7 8 9
3/3 6/6 10/10 1/2 1/1 1/4 1/6 4/5 3/3
Total
30/40 (75.0%)

  • Instructions

    Introduction to Statistics, Think & Do 4/e by Scott Stevens published by the Worldwide Center of Mathematics is now available through WebAssign. Introduction to Statistics includes over 200 assignable online homework problems, developed by the author to perfectly complement his textbook.
    Additional features of this textbook collection
    • Complete solutions for every problem, available to students at the instructor’s discretion
    • Complete eBook to enhance student interaction and provide a more affordable course solution
    Click here for a list of all of the questions coded in WebAssign. This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

Assignment Submission

For this assignment, you submit answers by question parts. The number of submissions remaining for each question part only changes if you submit or change the answer.

Assignment Scoring

Your last submission is used for your score.

1. 3/3 points  |  Previous Answers StevensStat4 1.P.012. My Notes
Question Part
Points
Submissions Used
1 2 3
1/1 1/1 1/1
1/50 1/50 4/50
Total
3/3
 
Attrition Rates: The rate at which students do not return to college is called the attrition rate. At State College, 270 of the 3000 Freshmen did not return for their Sophomore year. At State University, 390 of the 13,000 Freshman did not return for their Sophomore year.
(a) The attrition rate at State College is Correct: Your answer is correct. %.

(b) The attrition rate at State University is Correct: Your answer is correct. %.

(c) Which of the following statements is NOT true?
     Correct: Your answer is correct.
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2. 6/6 points  |  Previous Answers StevensStat4 2.P.017.v1. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6
1/1 1/1 1/1 1/1 1/1 1/1
2/50 1/50 3/50 2/50 4/50 1/50
Total
6/6
 
AM -vs- PM Test Scores: In my AM section of statistics there are 22 students. The scores of Test 1 are given in the table below. The results are ordered lowest to highest to aid in answering the following questions.
index 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
score 37 50 58 59 60 64 65 66 68 68 71 74 76 76 79 82 85 88 90 91 94 95
(a) The value of P90 is Correct: Your answer is correct. .

(b) Complete the 5-number summary.
Minimum  =  Correct: Your answer is correct.
Q1  =  Correct: Your answer is correct.
Q2  =  Correct: Your answer is correct.
Q3  =  Correct: Your answer is correct.
Maximum  =  Correct: Your answer is correct.
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3. 10/10 points  |  Previous Answers StevensStat4 3.P.001d. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6 7 8 9 10
1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
1/50 2/50 2/50 2/50 2/50 2/50 2/50 2/50 2/50 2/50
Total
10/10
 
American-Made Cars: Complete the cumulative and relative cumulative frequency table from the frequency table for the MPG ratings of 472 different American-Made cars. The cumulative frequencies should be whole numbers. Enter relative cumulative frequencies in percentage form rounded to 1 decimal place.
American-Made Cars
MPGFrequency
10 − 1460
15 − 19166
20 − 24159
25 − 2967
30 − 3420
American-Made Cars
Relative
CumulativeCumulative
MPGFrequency    Frequency
less than 14.5    Correct: Your answer is correct. Correct: Your answer is correct. %
less than 19.5 Correct: Your answer is correct. Correct: Your answer is correct. %
less than 24.5 Correct: Your answer is correct. Correct: Your answer is correct. %
less than 29.5 Correct: Your answer is correct. Correct: Your answer is correct. %
less than 34.5 Correct: Your answer is correct. Correct: Your answer is correct. %
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4. 1/2 points  |  Previous Answers StevensStat4 4.P.005. My Notes
Question Part
Points
Submissions Used
1 2
0/1 1/1
2/50 1/50
Total
1/2
 
Car Accidents: Of the reported 1642 car accidents in Stevens County last year, 933 of them occurred within 1 mile of the person's home. Round your answers to 3 significant digits*.
(a) If one of the reported car accidents is randomly selected, what is the probability that it occurred within 1 mile of the person's home?
WebAssign will check your answer for the correct number of significant figures. Incorrect: Your answer is incorrect.

(b) Estimate the probability that the next reported car accident in Stevens County will be within 1 mile of the person's home.
WebAssign will check your answer for the correct number of significant figures. Correct: Your answer is correct.


...............................................
*Significant Digits: Here are some probabilities expressed to 3 significant digits. You start counting digits from left to right starting with the first non-zero digit.
0.123      0.0123      0.00123      0.102      0.350      0.300
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5. 1/1 points  |  Previous Answers StevensStat4 5.P.009b. My Notes
Question Part
Points
Submissions Used
1
1/1
1/50
Total
1/1
 
Calculate the following binomial probability by either using one of the binomial probability tables, software, or a calculator using the formula below. Round your answer to 3 decimal places.
P(x | n, p) = 
n!
(n − x)! x!
 · px · qn − x    where    q = 1 − p
P(x = 16, n = 18, p = 0.90) = Correct: Your answer is correct.
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6. 1/4 points  |  Previous Answers StevensStat4 6.P.005def. My Notes
Question Part
Points
Submissions Used
1 2 3 4
1/1 0/1 0/1 0/1
2/50 1/50 2/50 2/50
Total
1/4
 
Potatoes: Suppose the weights of Farmer Carl's potatoes are normally distributed with a mean of 7.5 ounces and a standard deviation of 1.1 ounces.
(a) Carl only wants to sell the best potatoes to his friends and neighbors at the farmer's market. According to weight, this means he wants to sell only those potatoes that are among the heaviest 25%. What is the minimum weight required to be brought to the farmer's market? Round your answer to 2 decimal places.
Correct: Your answer is correct. ounces

(b) He wants to use the lightest potatoes as ammunition for his potato launcher but can only spare about 5% of his crop for such frivolities. What is the weight limit for potatoes to be considered for ammunition? Round your answer to 2 decimal places.
Incorrect: Your answer is incorrect. ounces

(c) Determine the weights that delineate the middle 90% of Carl's potatoes from the others. Round your answers to 2 decimal places.
from Incorrect: Your answer is incorrect. to Incorrect: Your answer is incorrect. ounces
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7. 1/6 points  |  Previous Answers StevensStat4 7.P.007abcde. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6
1/1 –/1 –/1 –/1 –/1 –/1
1/50 0/50 0/50 0/50 0/50 0/50
Total
1/6
 
Fair Coin? A coin is called fair if it lands on heads 50% of all possible tosses. You flip a game token 100 times and it comes up heads 61 times. You suspect this token may not be fair.
(a) What is the point estimate for the proportion of heads in all flips of this token? Round your answer to 2 decimal places.
Correct: Your answer is correct.

(b) What is the critical value of z (denoted zα/2) for a 90% confidence interval? Use the value from the table or, if using software, round to 2 decimal places.
zα/2 =

(c) What is the margin of error (E) for a 90% confidence interval? Round your answer to 3 decimal places.
E =

(d) Construct the 90% confidence interval for the proportion of heads in all tosses of this token. Round your answers to 3 decimal places.
< p <

(e) Are you 90% confident that this token is not fair?
    
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8. 4/5 points  |  Previous Answers StevensStat4 9.P.001. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5
1/1 1/1 0/1 1/1 1/1
1/50 1/50 1/50 1/50 1/50
Total
4/5
 
Sibling IQ Scores: There have been numerous studies involving the correlation and differences in IQ's among siblings. Here we consider a small example of such a study. We will test the claim that, on average, older siblings have a higher IQ than younger siblings. The results are depicted for a sample of 10 siblings in the table below. Test the claim at the 0.05 significance level.
Sibling    Older Sibling IQ    Younger Sibling IQ   difference  
Pair # (x) (y) d = x − y
1 84 79 5
2 87 89 −2
3 91 88 3
4 92 92 0
5 99 97 2
6 104 102 2
7 105 105 0
8 110 109 1
9 114 108 6
10 121 111 10
Mean 100.7 98.0 2.7
s 12.2 10.7 3.5
If you are using software, you should be able copy and paste the data by highlighting the entire table.

(a) The claim is that the mean difference is positive (μd > 0), what type of test is this?
     Correct: Your answer is correct.

(b) What is the test statistic? Round your answer to 2 decimal places.
t
d
 = Correct: Your answer is correct.
To account for hand calculations -vs- software, your answer must be within 0.01 of the true answer.

(c) What is the critical value of t? Use the answer found in the t-table or round to 3 decimal places.
tα = Incorrect: Your answer is incorrect.

(d) What is the conclusion regarding the null hypothesis?
     Correct: Your answer is correct.

(e) Choose the appropriate concluding statement.
     Correct: Your answer is correct.
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9. 3/3 points  |  Previous Answers StevensStat4 10.P.002abc. My Notes
Question Part
Points
Submissions Used
1 2 3
1/1 1/1 1/1
1/50 1/50 1/50
Total
3/3
 
Business/Economics: Below is the scatterplot, regression line, and corresponding statistics for price (x) -vs- number sold (y) data.
WebAssign Plot          Price -vs- Demand:
x = Price per item (in dollars)
y = Demand (number of items sold)

correlation coefficient:
r =
−0.890


regression equation:
ŷ = −89x + 1367


sample size:
n = 19

sample means:
x = $6.50    y = 787.3
Answer the following questions regarding the relationship between price (x) and demand (y).
(a) Is there a significant linear correlation between these variables?
     Correct: Your answer is correct.

(b) What percentage of the variation in demand can be explained by the linear relation to price? Enter your answer as a percentage with one decimal place.
Correct: Your answer is correct. %

(c) How many items would you expect to sell if the price was set at $8.50? Round your answer to the nearest whole number.
Correct: Your answer is correct. items
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