1. A survey of 25 grocery stores revealed that the mean price of a gallon of mil
ID: 3040160 • Letter: 1
Question
1. A survey of 25 grocery stores revealed that the mean price of a gallon of milk was $2.98, with a standard error of $0.10. If 90% and 95% confidence intervals were developed to estimate the true cost of a gallon of milk, what similarities would they have?
Both use the same t statistic
Both have the same confidence level
Both use the same z statistic
According to the central limit theorem, ________.
the sampling distribution of the sample means is approximately normally distributed
the population mean and the mean of all sample means are equal
increasing sample size decreases the dispersion of the sampling distribution
the sampling distribution of the sample means will be skewed
3.
Bones Brothers & Associates prepare individual tax returns. Over prior years, Bones Brothers has maintained careful records regarding the time to prepare a return. The mean time to prepare a return is 90 minutes and the standard deviation of this distribution is 14 minutes. Suppose 100 returns from this year are selected and analyzed regarding the preparation time. What is the standard error of the mean?
14 minutes
90 minutes
1.4 minutes
140 minutes
4.
The Office of Student Services at a large western state university maintains information on the study habits of its full-time students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal distribution with a standard deviation of six hours. Suppose we select a random sample of 144 current students. What is the probability that the mean of this sample is between 19 hours and 20 hours?
2.00
-2.00
0.4772
Cannot be calculated based on the given information.
5.
The Office of Student Services at a large western state university maintains information on the study habits of its full-time students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal distribution with a standard deviation of six hours. Suppose we select a random sample of 144 current students. What is the probability that the mean of this sample is between 19.25 hours and 21.0 hours?
0.0986
0.9544
0.9104
0.0160
6.
The average score of 100 students taking a statistics final was 70, with a standard deviation of 7. Assuming a normal distribution, what test score separates the top 5% of the students from the lower 95% of the students?
78.96
90.00
83.72
81.55
7.
The mean of all the sample means is ________.
µ
8.
The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the probability that a flight is less than 135 minutes?
0.50
0.25
1.00
0.00
10.
QUESTION 48
Which of the following is a characteristic of the normal probability distribution?
It's asymmetrical.
It's bell-shaped.
It's rectangular.
It's positively skewed.
Both use the same point estimate of the population mean
Both use the same t statistic
Both have the same confidence level
Both use the same z statistic
2.According to the central limit theorem, ________.
the sampling distribution of the sample means is approximately normally distributed
the population mean and the mean of all sample means are equal
increasing sample size decreases the dispersion of the sampling distribution
the sampling distribution of the sample means will be skewed
3.
Bones Brothers & Associates prepare individual tax returns. Over prior years, Bones Brothers has maintained careful records regarding the time to prepare a return. The mean time to prepare a return is 90 minutes and the standard deviation of this distribution is 14 minutes. Suppose 100 returns from this year are selected and analyzed regarding the preparation time. What is the standard error of the mean?
14 minutes
90 minutes
1.4 minutes
140 minutes
4.
The Office of Student Services at a large western state university maintains information on the study habits of its full-time students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal distribution with a standard deviation of six hours. Suppose we select a random sample of 144 current students. What is the probability that the mean of this sample is between 19 hours and 20 hours?
2.00
-2.00
0.4772
Cannot be calculated based on the given information.
5.
The Office of Student Services at a large western state university maintains information on the study habits of its full-time students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal distribution with a standard deviation of six hours. Suppose we select a random sample of 144 current students. What is the probability that the mean of this sample is between 19.25 hours and 21.0 hours?
0.0986
0.9544
0.9104
0.0160
6.
The average score of 100 students taking a statistics final was 70, with a standard deviation of 7. Assuming a normal distribution, what test score separates the top 5% of the students from the lower 95% of the students?
78.96
90.00
83.72
81.55
7.
The mean of all the sample means is ________.
µ
8.
The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the probability that a flight is less than 135 minutes?
0.50
0.25
1.00
0.00
10.
QUESTION 48
Which of the following is a characteristic of the normal probability distribution?
It's asymmetrical.
It's bell-shaped.
It's rectangular.
It's positively skewed.
Both use the same point estimate of the population mean
Explanation / Answer
1)Both use the same point estimate of the population mean
2) the sampling distribution of the sample means is approximately normally distributed
3)standard error of the mean =14/(100)1/2 =1.4 minute
4)
std error of mean =6/(144)1/2 =0.5
probability that the mean of this sample is between 19 hours and 20 hours=P(19<X<20)
=P((19-20)/0.5<Z<(20-20)/0.5)=P(-2<Z<0) =0.5-0.0228 =0.4772
5)
probability that the mean of this sample is between 19.25 hours and 21.0 hours=P(19.25<X<21)=P(-1.5<Z<2)
=.9772-.0668 =0.9104
6)
at 95t percentile z score =1.6449
hence score =70+1.6449*7=81.55
7)µ
8)probability that a flight is less than 135 minutes =(135-120)/(150-120) =0.5
10)It's bell-shaped.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.