Part 1 of 3 -
Question 1
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).
NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
The personnel department of a large corporation wants to estimate the family dental expenses of its employees to determine the feasibility of providing a dental insurance plan.
A random sample of 12 employees reveals the following family dental expenses (in dollars): 115, 370, 250, 593, 540, 225, 177, 425, 318, 182, 275, and 228.
Construct a 95% confidence interval estimate for the standard deviation of family dental expenses for all employees of this corporation.
Place your LOWER limit, in dollars rounded to 1 decimal place, in the first blank.
Do not use a dollar sign, a comma, or any other stray mark. For example, 123.4 would be a legitimate entry.
Place your UPPER limit, in dollars rounded to 1 decimal place, in the second blank.
Do not use a dollar sign, a comma, or any other stray mark. For example, 567.8 would be a legitimate entry.
Question 2
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).
NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
If a sample has 20 observations and a 95% confidence estimate for is needed, the appropriate value of the t-multiple required is .
Place your answer, rounded to 3 decimal places, in the blank. For example, 4.567 would be a legitimate entry.
Question 3
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).
NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
You are told that a random sample of 150 people from Iowa has been given cholesterol tests, and 60 of these people had levels over the "safe" count of 200.
Construct a 95% confidence interval for the population proportion of people in Iowa with cholesterol levels over 200.
Place your LOWER limit, rounded to 3 decimal places, in the first blank .
For example, .678 would be a legitimate entry.
Place your UPPER limit, rounded to 3 decimal places, in the second blank . For example, .789 would be a legitimate entry.
Question 4
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).
NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
The personnel department of a large corporation wants to estimate the family dental expenses of its employees to determine the feasibility of providing a dental insurance plan.
A random sample of 12 employees reveals the following family dental expenses (in dollars): 115, 370, 250, 593, 540, 225, 177, 425, 318, 182, 275, and 228.
Construct a 90% confidence interval estimate for the standard deviation of family dental expenses for all employees of this corporation.
Place your LOWER limit, in dollars rounded to 1 decimal place, in the first blank.
Do not use a dollar sign, a comma, or any other stray mark. For example, 123.4 would be a legitimate entry.
Place your UPPER limit, in dollars rounded to 1 decimal place, in the second blank.
Do not use a dollar sign, a comma, or any other stray mark. For example, 567.8 would be a legitimate entry.
Question 5 of 20 1.0 Points
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).
NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
The personnel department of a large corporation wants to estimate the family dental expenses of its employees to determine the feasibility of providing a dental insurance plan.
A random sample of 12 employees reveals the following family dental expenses (in dollars): 115, 370, 250, 593, 540, 225, 177, 425, 318, 182, 275, and 228.
Construct a 99% confidence interval estimate for the standard deviation of family dental expenses for all employees of this corporation.
Place your LOWER limit, in dollars rounded to 1 decimal place, in the first blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 98.4 would be a legitimate entry.
Place your UPPER limit, in dollars rounded to 1 decimal place, in the second blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 567.8 would be a legitimate entry.
Question 6
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
If a sample has 25 observations and a 99% confidence estimate for is needed, the appropriate value of the t-multiple required is .
Place your answer, rounded to 3 decimal places, in the blank.
For example, 3.456 would be an appropriate entry.
Question 7
Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation).
NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
A survey of 85 families showed that 36 owned at least one DVD player.
Find the 99% confidence interval estimate of the true proportion of families who own at least one DVD player.
Place your limits, rounded to 3 decimal places, in the blanks.
Place the lower limit in the first blank and the upper limit in the second blank When entering your answer do not use any labels or symbols other than the decimal point.
Simply provide the numerical values. For example, 0.123 would be a legitimate entry.
Part 2 of 3 -
Question 8
Compute P(t15 > 2.0) where t15 has a t-distribution with 15 degrees of freedom.
A.0.7639
B.0.03197
C.0.93606
D.0.96803
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Question 9
The t- distribution for developing a confidence interval for a mean has _____ degrees of freedom.
A.n - 2
B.n + 1
C.n
D.n - 1
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Question 10
If you are constructing a confidence interval for a single mean, the confidence interval will___________ with an increase in the sample size.
A.decrease
B.increase
C.increase or decrease, depending on the sample data
D.stay the same
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Question 11
In order to be accepted into a top university, applicants must score within the top 5% on the SAT exam.
Given that SAT test scores are normally distributed with a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university?
A.1330
B.1400
C.1250
D.1100
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Question 12
In constructing a confidence interval estimate for a population mean, when we replace with the sample standard deviation (s), we introduce a new source of variability and the sampling distribution we use is:
A.the normal distribution
B.F- distribution
C.chi-square distribution
D.t -distribution
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Question 13
Which of the following will make a confidence interval narrower and more precise?
A.Smaller sample size and higher confidence level
B.Larger sample size and lower confidence level
C.Larger sample size and higher confidence level
D.Smaller sample size and lower confidence level
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Question 14
Confidence intervals are a function of which of the following three things?
A.The population, the sample, and the standard deviation
B.The data in the sample, the confidence level, and the sample size
C.The sample, the variable of interest, and the degrees of freedom
D.The sampling distribution, the confidence level, and the degrees of freedom
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Question 15
In a study of elephants a researcher wishes to determine the average weight of a certain subspecies of elephants.
From previous studies, the standard deviation of the weights of elephants in this subspecies is known to be 1500 pounds.
How many elephants does the researcher need to weigh so that he can be 80% confident that the average weight of elephants in his sample is within 350 pounds of the true average weight for this subspecies?
A.31
B.166
C.50
D.39
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Question 16
The upper limit of the 90% confidence interval for the population proportion p, given that n = 100; and p^= 0.20 is
A.0.2658
B.0.7342
C.0.4684
D.0.5316
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Question 17
A sample of 23 European countries found that the variance of life expectancy was 7.3 years.
What is the 95% confidence interval estimate for the variance of life expectancy in Europe?
A.27.2 < < 118.3
B.5.6 < < 10.3
C.4.4 < < 14.6
D.28.9 < < 115.0
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Question 18
A previous study of nickels showed that the standard deviation of the weight of nickels is 150 milligrams.
How many nickels does a coin counter manufacturer need to weigh so that she can be 98% confident that her sample mean is within 25 milligrams of the true average weight of a nickel?
A.36
B.196
C.239
D.139
Question 19
The lower limit of the 95% confidence interval for the population proportion p, given that n = 300; and = 0.10 is 0.1339.
True
False
Question 20
The upper limit of the 90% confidence interval for the population proportion p, given that n = 100; and p^= 0.20 is 0.2341.
True
False