In the past, 75% of the tourists who visited Chattanooga went to see Rock City. The management of Rock City recently cancelled its extensivesive promotional campaign. They are interested in determining whether canceling the promotional campaign has actual
H0: P 0.75 Ha: P > 0.75
(Round your answer to three decimal places.) In a one-tail (upper tail) hypothesis test situation, the test statistic is determined to be t = 2.692. The sample size was 45. The p-value for this test is
0.0050
When the p-value is used for hypothesis testing, the null hypothesis is rejected if
p-value ?
After computing a confidence interval, the user believes the results are meaningless because the width of the interval is too large. Which one of the following is the best recommendation?
Increase the sample size.
As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution
becomes smaller
The p-value
must be a number between zero and 1
What type of error occurs if you reject H0 when, in fact, it is true?
Type I
The probability distribution of the sample mean is called the
sampling distribution of the mean
The purpose of statistical inference is to provide information about the
population based upon information contained in the sample
The t value for a 95% confidence interval estimation with 24 degrees of freedom is
2.064
As the sample size increases, the margin of error
decreases
Which of the following distributions can be used as an approximation to the binomial distribution?
normal
Whenever the population has a normal probability distribution, the sampling distribution of x is a normal probability distribution for
any sample size
In a study of managers at a large firm, managers are categorized into three groups according to their division (field, production, or corporate). A simple random sample is taken from each group, and data are collected on each manager in the sample. The sa
stratified random sampling
A simple random sample of 6 computer programmers in Houston, Texas revealed the gender of the programmers and the following information about their weekly incomes.
Programmer Weekly Income Gender
A $250 M
B 270 M
C 285 F
D 240 M
E 255 M
F 290 F
Determine
0.667
An interval estimate is a range of values used to estimate
a population parameter
The value added and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the
margin of error
A simple random sample of 100 observations was taken from a very large population. The sample mean is 80 and the population standard deviation is 12. The standard deviation of the sampling distribution of the sample means is
1.20
A random sample of 100 people was taken. Eighty-five of the people in the sample favored Candidate A. We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly different than 80%. If the test
0.2113
In hypothesis testing, the tentative assumption about the population parameter is
a null hypothesis
A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a sample standard deviation of 240.
The 95% confidence interval for the average SAT scores of those applying for merit scholarships is
1340.05 to 1459.95
As the test statistic for an upper tail hypothesis test becomes larger, the p-value
gets smaller
The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. We want to test to determine whether or not th
2.00
At a confidence level of 95% a confidence interval for a population proportion is determined to be 0.65 to 0.75. If the confidence level is increased, the interval for the population proportion
becomes wider
As the sample size increases, the
standard error of the mean decreases
A subset of a population selected to represent the population is
a sample
In computing the standard error of the mean, the finite population correction factor is used when
n/N > 0.05
The number of random samples (without replacement) of size 3 that can be drawn from a population of size 5 is
10
Random samples of size 81 are taken from an infinite population whose mean and standard deviation are 200 and 18, respectively. The distribution of the population is unknown. The mean and the standard error of the mean are
200 and 2
A population of 1,000 students spends an average of $10.50 a day on dinner. The standard deviation of the expenditure is $3. A simple random sample of 64 students is taken.
What is the shape of the sampling distribution of the sample mean?
normal
A population of 1,000 students spends an average of $10.50 a day on dinner. The standard deviation of the expenditure is $3. A simple random sample of 64 students is taken.
What is the expected value of the sampling distribution of the sample mean? Round
10.5
A population of 1,000 students spends an average of $10.50 a day on dinner. The standard deviation of the expenditure is $3. A simple random sample of 64 students is taken.
What is the standard deviation of the sampling distribution of the sample mean? Ro
0.375
A population of 1,000 students spends an average of $10.50 a day on dinner. The standard deviation of the expenditure is $3. A simple random sample of 64 students is taken.
What is the probability that these 64 students will spend a combined total of more
0.036
The SAT scores have an average of 1200 with a standard deviation of 60. A sample of 36 scores is selected.
What is the probability that the sample mean will be larger than 1224? Round your answer to three decimal places.
0.008
The SAT scores have an average of 1200 with a standard deviation of 60. A sample of 36 scores is selected.
What is the probability that the sample mean will be less than 1230? Round your answer to three decimal places.
0.999
The SAT scores have an average of 1200 with a standard deviation of 60. A sample of 36 scores is selected.
What is the probability that the sample mean will be between 1200 and 1214? Round your answer to three decimal places.
0.419
A population has a mean of 180 and a standard deviation of 24. A sample of 64 observations will be taken. The probability that the sample mean will be between 183 and 186 is
0.1359
A simple random sample of 6 computer programmers in Houston, Texas revealed the gender of the programmers and the following information about their weekly incomes.
Programmer
Weekly Income
Gender
A
$250
M
B
270
M
C
285
F
D
240
M
E
255
M
F
290
F
Determine
0.333
A bank has kept records of the checking balances of its customers and determined that the average daily balance of its customers is $300 with a standard deviation of $48. A random sample of 144 checking accounts is selected. What is the probability that t
0.9772
Use Excel to determine the z value for a 90.0% confidence interval estimation is
1.645
From a population with a variance of 900, a sample of 225 items is selected. At 95% confidence, the margin of error for the population mean is
3.92
A sample of 225 elements from a population with a standard deviation of 75 is selected. The sample mean is 180. The 95% confidence interval for the population mean is
170.2 to 189.8
In order to estimate the average time spent on the computer terminals per student at a local university, data were collected for a sample of 81 business students over a one-week period. Assume the population standard deviation is 1.8 hours.
If the sample
8.48 to 9.52 hours
A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.
If we want to provide a 95% confidence interval for the SAT scores, the degrees of freedom for reading the critical va
63
Using the Excel function (t.inv) determine the t value for a 95% confidence interval estimation with 24 degrees of freedom is
2.064
A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.
Using the Excel function (t.inv) the "t" value for a 95% confidence interval for the mean SAT score is
1.998
A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.
The margin of error at 95% confidence is
59.95
A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240.
The 95% confidence interval for the SAT scores is
1340.05 to 1459.95
A random sample of 64 students at a university showed an average age of 25 years and a sample standard deviation of 2 years. The 98% confidence interval for the true average age of all students in the university is
24.4 to 25.6
For which of the following values of P is the value of P(1 - P) maximized?
P = 0.50
The sample size needed to provide a margin of error of 2 or less for the population mean with a .95 probability when the population standard deviation equals 11 is
117
It is known that the population variance equals 484. With a 0.95 probability, the sample size that needs to be taken if the desired margin of error is 5 or less is
75
A random sample of 1000 people was taken. Four hundred fifty of the people in the sample favored Candidate A. The 95% confidence interval for the true proportion of people who favors Candidate A is
0.419 to 0.481
In a random sample of 100 observations, = 0.2. The 95.44% confidence interval for P is
0.120 to 0.280
A machine that produces a major part for an airplane engine is monitored closely. In the past, 10% of the parts produced would be defective. With a .95 probability, the sample size that needs to be taken if the desired margin of error is .04 or less is
217
The average manufacturing work week in metropolitan Chattanooga was 40.1 hours last year. It is believed that the recession has led to a reduction in the average work week. To test the validity of this belief, the hypotheses are
H0: m � 40.1 Ha: m < 40.1
A machine is designed to fill toothpaste tubes with 5.8 ounces of toothpaste. The manufacturer does not want any underfilling or overfilling. The correct hypotheses to be tested are
H0: m = 5.8 Ha: m � 5.8
The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of their tires has increased. In order to test the validity of their belief, the
H0: m 40,000 Ha: m > 40,000
In the past, 75% of the tourists who visited Chattanooga went to see Rock City. The management of Rock City recently undertook an extensive promotional campaign. They are interested in determining whether the promotional campaign actually increased the pr
H0: P 0.75 Ha: P > 0.75
Your investment executive claims that the average yearly rate of return on the stocks she recommends is at least 10.0%. You plan on taking a sample to test her claim. The correct set of hypotheses is
H0: m 10.0% Ha: m < 10.0%
The sales of a grocery store had an average of $8,000 per day. The store introduced several advertising campaigns in order to increase sales. To determine whether or not the advertising campaigns have been effective in increasing sales, a sample of 64 day
m < 8000
Refer to Question 1. The value of the test statistic is
2.0
Refer to Questions 1 & 2. The p-value is
0.0228
Refer to Question 3. If alpha is .05, the correct conclusion is
reject the null hypothesis
If a hypothesis test leads to the rejection of the null hypothesis,
a Type I error may have been committed
What type of error occurs if you fail to reject H0 when, in fact, it is not true?
Type II
The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. We want to test to determine whether or not th
2.00
(Round your answer to three decimal places.) In a one-tail (upper tail) hypothesis test situation, the test statistic is determined to be t = 2.692. The sample size was 45. The p-value for this test is
0.005
A random sample of 100 people was taken. Eighty-five of the people in the sample favored Candidate A. We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 80%. If the test stat
0.1056
For a one-tailed test (upper tail), a sample size of 26 at 90% confidence, t =
1.316
At a confidence level of 96% a confidence interval for a population proportion is determined to be 0.65 to 0.75. If the confidence level is increased, the interval for the population proportion
becomes wider
Which of the following best describes the form of the sampling distribution of the sample proportion?
It is approximately normal as long as np >_ 5 and n(1-p) >_5.