stat final

A government agency was charged by the legislature with estimating the length of time it takes citizens to fill out various forms. The agency generated an 85% confidence interval, a 90% confidence interval, and a 99% confidence interval, all of which are listed below. Which one is the 85% confidence interval?

(12.63, 12.97)

The following table gives the probabilities of all parts made from two production lines at a factory whether they are good or defective . A part is randomly selected from this factory. The probability that this part is defective is about

0.10

The probability distribution of a discrete random variable X is given by x01234p(x) ? 0.30 0.10 0.20 0.10 Find the missing probability in the table.

0.30

The following two-way contingency table gives the breakdown of the population of adults in a particular locale according to highest level of education and whether or not the individual regularly takes dietary supplements: An adult is selected at random. The probability that the person's highest level of education is an undergraduate degree is 0.37 .

0.37

The probability distribution of a discrete random variable x is shown in the following table: x01234P(x) p0.34 0.160.100.02 Find the value of p, the missing probability in the table.

0.38

The following two-way contingency table gives the breakdown of the voters in a particular locale according to gender and political party preference. A person is selected at random from this population. Vote for Democratic PartyVote for Republican PartyMale0.150.25Female0.400.20 Let A be the event that the selected person will vote for Republican party; B be the event that the selected person is a Male. Find

0.60

The following two-way contingency table gives the breakdown of the population of adults in a particular locale according to highest level of education and whether or not the individual regularly takes dietary supplements:

0.65

The probability distribution of a discrete random variable x is shown in the following table: x12345P(x) 0.24 0.20 0.37 0.05 0.14 Find P(x≥2).

0.76

Let x be a discrete random variable with the following probability distribution: x-20129P(x)0.1 0.2 0.3 0.2 0.2 Find P(x>−1)

0.9

Cell phone bills for a city's residents have a mean of $64 and a standard deviation of $14. Random samples of 100 bills are drawn from this population, and the mean of each sample is found. What is the sampling error of the mean?

1.4

A university dean wants to know how many credits students are taking. They randomly sample some students and put the results in the histogram below.

19

The average sales price of single-family houses in Charlotte is $350,000 with a standarddeviation of $40,000. A random sample of 100 single-family houses in Charlotte isselected. Let x¯ represent the mean sales price of the sample. What is the mean of the sampling distribution?

350,000

A company conducts a survey of 1000 randomly selected individuals to get their overall impressions of the past year. Results are shown below. What is the probability that the next person surveyed has a positive impression?

410/1000 = 0.41

A company conducts a survey of 1000 randomly selected individuals to get their overall impressions of the past decade. Results are shown below. What is the probability that the next person surveyed has a positive impression?

410/1000=0.41

Cell phone bills for a city's residents have a mean of $64 and a standard deviation of $14. Random samples of 100 bills are drawn from this population, and the mean of each sample is found. What is the mean of the sampling distribution?

64

If every else remain the same which of the following confidence level will result the widest confidence interval?

99%

How would you find the mean of data in the range B1 to B10 in Excel?

= AVERAGE(B1:B10)

How would you find the mean of data in the range B1 to B6 in Excel?

= AVERAGE(B1:B6)

Using Excel, how would you find the standard deviation for a sample of data located in cells A1 to A10 ?

= STDEV.S(A1:A10

Using Excel, how would you find the standard deviation for a sample of data located in cells A1 to A10?

= STDEV.S(A1:A10)

A nutritionist claims that the average amount of sugar in a 16 oz soda is at least 50 g. He randomly samples 10 sodas and finds they contain an average of 54 g of sugar with a standard deviation of 3 g. Assume the population is normally distributed and use α=0.10to test the claim. Which function in Excel finds the test statistic?

=(54-50)/(3/SQRT(10)

A diabetic claims that the average cost of insulin per year for a Type 1 diabetic is $5,705. She takes a sample of 100 Type 1 diabetics and finds their average cost is $5, 912 with a standard deviation of $300. Use α=0.05to test the claim. Which function in Excel finds the test statistic?

=(5912-5705)/(300/SQRT(100))

A survey shows that people use cell phones an average of 1.6 years with a standard deviation of 0.3 years. A user is randomly selected. If cell phone use is normally distributed, we can use Excel to calculate the probability that the randomly selected user uses their phone for more than 1 year with the function:

=1 - NORM.DIST(1, 1.6, 0.3, TRUE)

A survey shows that people use cell phones for an average of 1.6 years with a standard deviation of 0.3 years. A user is randomly selected. If cell phone use is normally distributed, we can use Excel to calculate the probability that the randomly selected user uses their phone for more than 1 year with the function:

=1 - NORM.DIST(1, 1.6, 0.3, TRUE)

A sociologist wishes to test H0:μ≤42 vs. Ha:μ>42. The sociologist takes a sample of size 100 and calculates a standardized test statistic of 2.34. To calculate a p-value for the test in Excel, the sociologist should use:

=1-NORM.DIST(2.34, 0, 1, TRUE)

Let Z be the random variable which has the standard normal distribution. Which of the following Excel functions will find P(Z<−0.65) ?

=NORM.DIST(-0.65, 0, 1, TRUE)

In the test of hypotheses H0:μ≥100 vs Ha:μ<100 . A sample of size 81 yields the standardized test statistic −1.50 . Which function in Excel finds the p-value?

=NORM.DIST(-1.50, 0,1,TRUE)

A survey shows that people use cell phones for an average of 1.6 years with a standard deviation of 0.3 years. A user is randomly selected. If cell phone use is normally distributed, we can use Excel to calculate the probability that the randomly selected user uses their phone for less than 1 year with the function:

=NORM.DIST(1, 1.6, 0.3, TRUE)

Household credit card debt in a certain region has a mean of $16,890 and a standard deviation of $4,220. Calculate the probability that the mean credit card debt of a random sample of 35 households would be $16,000 or less.

=NORM.DIST(16000, 16890, 4220/SQRT(35), TRUE)

A randomly selected sample of size 17 is taken. Assume the population is normally distributed. Which function finds the probability that t is less than 1.4?

=T.DIST(1.4, 16, TRUE)

In a situation of hypothesis testing, what happens when the null hypothesis H0 is wrongly rejected when it is actually true?

A Type I error occurs

A researcher wishes to estimate the proportion of all adults who own a cell phone. He takes a random sample of 2000 adults; 1650 of them own a cell phone. The population of interest to the researcher is

A university dean wants to know how many credits students are taking. They randomly sample some students and put the results in the histogram below.

The score made by a particular student on a national standardized exam is the 75th percentile. This means that

About 75% of all scores on the exam were equal to or less than his.

The score made by a particular student on a national standardized exam is the 75th percentile. This means that

About 75% of all scores on the exam were lower than his.

The Department of Education wishes to estimate the proportion of all college students who have a job off-campus. It surveyed 1600 randomly selected students; 451 had such jobs. The population of interest to the Department of Education is:

All college students.

There were 1000 students who took part in the common final exam on STAT 1222. The average is 70 with a standard deviation 8. If a student got a z-score of 3.10 in this exam, which of the following is true?

Compared with other students in this exam, this student did extremely well.

A diabetic claims that the average cost of insulin per year for a Type 1 diabetic is $5,705. She takes a sample of 100 Type 1 diabetics and finds their average cost is $5, 800 with a standard deviation of $575. Use α=0.05to test the claim. What are the hypotheses?

H0= u=5705 Ha: u=/ 5705

Which tables give valid probability distribution for a discrete random variable?

I and IV

Seven bear tracks were found in the woods. Their length was measured in inches and recorded in the table below: If another bear track was found that was 8 in, what would happen to the mean?

It would decrease.

Given the following sample data 8.6 8.4 9.3 10.5 9.8 8.9 10.2 If a new number (=11) is added to this data, what would happen to the mean?

It would increase.

In the test of hypothesis H0:μ=100 vs . Ha:μ≠100, we already have the p-value for this test: P-value=0.025. Which of the following (with the reason) will be correct with significance level at .05?

Reject H0 since the P-value is less than the significance level.

A nutritionist claims that the average amount of sugar in a 16 oz soda is at least 50 g. He randomly samples 10 sodas and finds they contain an average of 54 g of sugar with a standard deviation of 3 g. Assume the population is normally distributed and use α=0.10to test the claim. In this scenario, the appropriate test statistic is:

T=x-u0/ s/n

Which of the following statements would correspond to an alternative hypothesis?

The population mean is not 22

Which of the following statements would correspond to a null hypothesis?

The population proportion is at most 0.75

Let Z be the random variable which has the standard normal distribution. Which of the following is NOT a property of the the standard normal distribution?

The potential values of Z are from −3 to 3.

A survey was conducted to estimate the proportion of all eligible voters who actually voted in the previous presidential election. The survey investigated 2000 eligible voters and found that 1360 or 68% of them actually voted. Which of the following is true?

The sample size is 2000

You are tossing a fair coin. Let X=1 if you observe a head and X=0 if you observe a tail. Which of the following tables represents the resulting probability distribution for the random variable X?

X 01P(X)1212

In a random sample of 100 adults, 27 say they are in favor of outlawing cigarettes. Let p be the proportion of all adults who are in favor of outlawing cigarettes. A researcher wishes to test the following hypotheses: H0:p=0.23;Ha:p≠0.23. In this scenario, the appropriate test statistic is:

Z=p-po/po qo/n

The mean score on a standardized math exam is 75; the standard deviation is 8. Zack is told that the z-score of his exam score is -1.25. Which of the following statements is true?

Zack's score is below the class average

The mean score on a standardized math exam is 77.2; the standard deviation is 9.5. Zack is told that thez-score of his exam score is 1.3. Is Zack's score above average or below average? above average

above average

The target temperature for a hot beverage the moment it is dispensed from a vending machine is 169°F.A consumer organization believes that a particular brand of machine dispenses beverages whose temperature exceeds 169°F. In this scenario, a type I error would be: (a) Deciding that the beverages do not exceed 169°F when they do.(b) Deciding that the beverages exceed 169°F when they don't.

b

Mean median and mode are all measures of the... while variance and standard deviation measure

center.. spread

A diabetic claims that the average cost of insulin per year for a Type 1 diabetic is $5,705. She takes a sample of 100 Type 1 diabetics and finds their average cost is $5, 912 with a standard deviation of $300. Use α=0.05to test the claim. If the decision is to reject H0, what should the interpretation be? There is enough evidence to

enough evidence reject the claim

A diabetic claims that the average cost of insulin per year for a Type 1 diabetic is $5,705. She takes a sample of 100 Type 1 diabetics and finds their average cost is $5, 800 with a standard deviation of $575. Use α=0.05to test the claim. Suppose the p-value is 0.0856. What is the decision? Fail to reject H_0

fail to reject H-O

18% of victims of financial fraud know the perpetrator of the fraud personally. Let X be the number of people in a random sample of 24 victims of financial fraud who knew the perpetrator personally. Then X is binomial with:

n=24 p=0.18

A nutritionist claims that the average amount of sugar in a 16 oz soda is at least 50 g. He randomly samples 10 sodas and finds they contain an average of 54 g of sugar with a standard deviation of 3 g. Assume the population is normally distributed and use α=0.10to test the claim. Suppose the p-value is 0.0854. What is the decision?

reject H-O

In a random sample of 14 people, the mean body mass index (BMI) was 25.7 and the standard deviation was 5.12. Assume the body mass indexes are normally distributed. Which distribution will you use to calculate a confidence interval for BMI?

t distribution

The level of significance (α) is _______________.

the maximum probability of making a Type I error

Let X be the number you observe when you randomly roll a fair 6-sided die. An experiment consists of taking 1000 such rolls (i.e., sample size n = 1000). Let X¯ be the average value of these 1000 rolls. Does X¯ follow approximately a normal distribution?

true

The probability distribution of a discrete random variable X is given by x01234p(x) 0.10 0.30 0.40 0.10 0.10 Which of the following formula will be used to find the mean of the distribution?

u=Ex*p(x)

Which of the following is NOT a property of the standard normal distribution?

uniform in shape

The standard deviation of a data set measures the ___________ of the dataset.

variability

Let X be the number you observe when you randomly roll a fair 6-sided die and suppose that the distribution of X is unknown. An experiment consists of taking 1000 such rolls (i.e., sample size n = 1000). Let X¯ be the average of 1000 rolls. Does X¯ follow approximately a normal distribution?

yes

In a random sample of 55 people, the mean body mass index (BMI) was 25.7 and the standard deviation was 5.12. Assume the body mass indexes are normally distributed. Which distribution will you use to calculate a confidence interval for BMI?

z distribution