Southpaw reports Simon reads a newspaper report claiming that 12% of all adults in the United States are left-handed. He wonders if this figure holds true at the large community college he attends.
Simon chooses an SRS of 100 students and records whether each student is right- or left-handed.
What is the parameter of interest?
What is the statistical symbol?
Simon reads a newspaper report claiming that 12% of all adults in the United States are left-handed. He wonders if this figure holds true at the large community college he attends. Simon chooses an SRS of 100 students and records whether each student is right- or left-handed.
What is the null and alternative hypothesis?
Mr. Starnes believes that less than 75% of the students at his school did their math homework last night.
The math teachers inspect the homework assignments from a random sample of 50 students at the school. Only 68% of the students did their math homework.
What is the parameter of interest?
What is the statistical symbol?
Mr. Starnes believes that less than 75% of the students at his school did their math homework last night.
The math teachers inspect the homework assignments from a random sample of 50 students at the school. Only 68% of the students did their math homework.
What is the null and alternative hypothesis?
Read carefully!
Philly fanatics? Nationally, the proportion of red cars on the road is 0.12. A statistically minded fan of the Philadelphia Phillies (whose team color is red) wonders if Phillies fans are more likely to drive red cars. One day during a home game, he takes a random sample of 210 cars parked at Citizens Bank Park (the Phillies home field), and counts 35 red cars.
What is the null and alternative hypothesis?
Read carefully!
Philly fanatics? Nationally, the proportion of red cars on the road is 0.12. A statistically minded fan of the Philadelphia Phillies (whose team color is red) wonders if Phillies fans are more likely to drive red cars. One day during a home game, he takes a random sample of 210 cars parked at Citizens Bank Park (the Phillies home field), and counts 35 red cars.
The fan came up with a P-value for the test = 0.0187.
Assume an alpha level of 0.05.
Interpret the P-value in context. See your notes for the sentence frame.
"Assuming.....(null hypothesis is true, use context), there is a ... (p-value probability) of getting... (give the sample results)... or 'higher/lower' purely by chance."
I will grade this question. Check your notes for 8.1 carefully!
Philly fanatics? Nationally, the proportion of red cars on the road is 0.12. A statistically minded fan of the Philadelphia Phillies (whose team color is red) wonders if Phillies fans are more likely to drive red cars. One day during a home game, he takes a random sample of 210 cars parked at Citizens Bank Park (the Phillies home field), and counts 35 red cars.
The fan came up with a P-value for the test = 0.0187.
Assume an alpha level of 0.05.
What conclusion would you make about the proportion of red cars owned by Philly fans?
I will grade this question. Check your notes for 8.1 carefully!
Simon reads a newspaper report claiming that 12% of all adults in the United States are left-handed. He wonders if this figure holds true at the large community college he attends. Simon chooses an SRS of 100 students and finds that 16 of them are left-handed. He uses the data to perform a test of:
H0: p = 0.12 versus Ha: p ≠ 0.12,
where p is the true proportion of lefties at his community college. The test yields a P-value of 0.2184.
Interpret the p-value for this study. Check your notes for Lesson 8.1.
"Assuming.....(null hypothesis is true, use context), there is a ... (p-value probability) of getting... (give the sample results)... or higher/lower purely by chance in random samples of ..."
I will grade this question.
Simon reads a newspaper report claiming that 12% of all adults in the United States are left-handed. He wonders if this figure holds true at the large community college he attends. Simon chooses an SRS of 100 students and finds that 16 of them are left-handed. He uses the data to perform a test of:
H0: p = 0.12 versus Ha: p ≠ 0.12,
where p is the true proportion of lefties at his community college. The test yields a P-value of 0.2184. What conclusion would you make for the significance level of α = 0.05?
Simon reads a newspaper report claiming that 12% of all adults in the United States are left-handed. He wonders if this figure holds true at the large community college he attends. Simon chooses an SRS of 100 students and finds that 16 of them are left-handed. He uses the data to perform a test of:
H0: p = 0.12 versus Ha: p ≠ 0.12,
where p is the true proportion of lefties at his community college. The test yields a P-value of 0.2184. Define and then describe a Type I Error:
Simon reads a newspaper report claiming that 12% of all adults in the United States are left-handed. He wonders if this figure holds true at the large community college he attends. Simon chooses an SRS of 100 students and finds that 16 of them are left-handed. He uses the data to perform a test of:
H0: p = 0.12 versus Ha: p ≠ 0.12,
where p is the true proportion of lefties at his community college. The test yields a P-value of 0.2184. Define and then describe a Type II Error:
High blood pressure? A company markets a computerized device for detecting high blood pressure. The device measures an individual’s blood pressure once per hour at a randomly selected time throughout a 12-hour period. Then it calculates the mean systolic (top number) pressure for the sample of measurements. Based on the sample results, the device performs a test of:
H0: μ = 130 versus Ha: > 130,
where μ is the person’s true mean systolic pressure. Describe a Type I error in this setting.
High blood pressure? A company markets a computerized device for detecting high blood pressure. The device measures an individual’s blood pressure once per hour at a randomly selected time throughout a 12-hour period. Then it calculates the mean systolic (top number) pressure for the sample of measurements. Based on the sample results, the device performs a test of:
H0: μ = 130 versus Ha: > 130,
where μ is the person’s true mean systolic pressure.
Describe a Type II error in this setting.
Based on your answers to #12 & 13, in this scenario, which type of error would be worse?
Type I or Type II?
Explain why or why not.
Use complete sentences that make sense and answer the question.
I will grade this answer.
The manager of a fast-food restaurant wants to reduce the proportion of drive-thru customers who have to wait longer than 2 minutes to receive their food after placing an order.
Based on store records, the proportion of customers who had to wait longer than 2 minutes was p = 0.63.
To reduce this proportion, the manager assigns an additional employee to assist with drive-thru orders. The manager would like to carry out a significance test at the α = 0.10 significance level.
Select the null and alternative hypothesis below.
Then define the parameter of interest.
During the next month, the manager collects data on wait times from a random sample of 250 drive-thru orders, and finds that only 141 of the customers have to wait longer than 2 minutes.
What is the value of the sample proportion from above?
Round to three places past the decimal.
What is the evidence that the store manager has that there might be a difference in wait time?
Hint: what evidence do you have from the sample that allows you to determine the Ha?
I will grade this question when I return on Monday.
What is the conclusion for the significance test using a significance level (alpha level) of 10%?
A recent report claimed that 13% of students typically walk to school. DeAnna thinks that the proportion is higher than 0.13 at her large elementary school. She surveys a random sample of 150 students and finds that 23 typically walk to school.
DeAnna would like to carry out a test at the α = 0.05 significance level.
Select the null and alternative hypothesis below.
Then define the parameter of interest.
A recent report claimed that 13% of students typically walk to school. DeAnna thinks that the proportion is higher than 0.13 at her large elementary school. She surveys a random sample of 150 students and finds that 23 typically walk to school.
DeAnna would like to carry out a test at the α = 0.05 significance level.
What is the sample proportion?
Round to 3 places past the decimal.
What is the evidence that DeAnna has that there might be a difference in the proportion of students who walk to school?
Hint: what evidence do you have from the sample that allows you to determine the Ha?
I will grade this question when I return on Monday.
What is the conclusion for the significance test using a significance level (alpha level) of 5%?
Based on store records, the proportion of customers who had to wait longer than 2 minutes was p = 0.63.
To reduce this proportion, the manager assigns an additional employee to assist with drive-thru orders. The manager would like to carry out a significance test at the α = 0.10 significance level.
During the next month, the manager collects data on wait times from a random sample of 250 drive-thru orders, and finds that only 141 of the customers have to wait longer than 2 minutes.
Check if the conditions for performing the significance test are met.
Remember po represents the proportion from the Null Hypothesis.
A recent report claimed that 13% of students typically walk to school. DeAnna thinks that the proportion is higher than 0.13 at her large elementary school. She surveys a random sample of 150 students and finds that 23 typically walk to school.
DeAnna would like to carry out a test at the α = 0.05 significance level.
Check if the conditions for performing the significance test are met.
Remember po represents the proportion from the Null Hypothesis.