Statistics 221 BYU-I 57 correct solutions.
Statistics 221 BYU-I 57 correct solutions.
Which of the following variables is/are quantitative? - ANSWER The number of people in a randomly
selected classroom on campus.
The weight of a BYU-I student.
Students in an Introductory Statistics class at BYU-Idaho were studying prices of cold cereal at grocery
stores in Rexburg. To get a sample of cold cereal prices, they went to Albertson's and rolled a die to
decide which box from the left of the top shelf they would start on. They then recorded every 6th cereal
after the first, moving from left to right down the shelves, recording the name, size, and price of each
cereal in their sample. Is this study an experiment or an observational study, and why? - ANSWER An
observational study, because the students did not impose any treatment on the cereals.
Daniel was doing a statistical study. In which step of the statistical process is he engaged when he
creates a histogram of his data and calculates a sample mean? - ANSWER Describe the Data
In order to estimate the average weight of all adults in the state of Idaho, you randomly select 50 adults
from each county in Idaho. Use this information for all the parts.
Part 1: What type of sampling method was done here? - ANSWER Stratified Sample
In order to estimate the average weight of all adults in the state of Idaho, you randomly select 50 adults
from each county in Idaho. Use this information for all the parts.
Part 2: What is the population in your study above? - ANSWER The weights of all adults in the state of
Idaho.
You would like to test if females like math more than males do. You collect a sample of 100 males and
57 females. Among the 100 males, 32 say they like math. Among the females, 21 say they like math. Use
this information for all the parts.
Part 1: What is the null and alternative hypothesis? - ANSWER H0: P male=P female
HA: P male<P female
, Statistics 221 BYU-I 57 correct solutions.
You would like to test if females like math more than males do. You collect a sample of 100 males and
57 females. Among the 100 males, 32 say they like math. Among the females, 21 say they like math. Use
this information for all the parts.
What is the p-value for your test? - ANSWER .269
You would like to test if females like math more than males do. You collect a sample of 100 males and
57 females. Among the 100 males, 32 say they like math. Among the females, 21 say they like math. Use
this information for all the parts.
Part 3: Are the requirements for the above test satisfied? - ANSWER Yes, both and are larger than 10 for
both groups.
Tanker trucks are designed to carry huge quantities of gasoline from refineries to filling stations. A
factory that manufactures the tank of the trucks claims to manufacture tanks with a capacity of 8550
gallons of gasoline. The actual capacity of the tanks is normally distributed with mean gallons and
standard deviation gallons.
Part 1: What is the probability that a randomly chosen truck will have a capacity greater than 8528
gallons? - ANSWER .908
Tanker trucks are designed to carry huge quantities of gasoline from refineries to filling stations. A
factory that manufactures the tank of the trucks claims to manufacture tanks with a capacity of 8550
gallons of gasoline. The actual capacity of the tanks is normally distributed with mean gallons and
standard deviation gallons.
Part 2: Suppose that a simple random sample of tanks is selected and the sample mean capacity is found
to be 8550 gallons. What is the z-score corresponding to this sample mean? - ANSWER 2.336
Tanker trucks are designed to carry huge quantities of gasoline from refineries to filling stations. A
factory that manufactures the tank of the trucks claims to manufacture tanks with a capacity of 8550
gallons of gasoline. The actual capacity of the tanks is normally distributed with mean gallons and
standard deviation gallons.
Part 3: What is the probability that a sample of size 20 will have a mean between 8538 and 8550
gallons? - ANSWER .975
In order to decide if a certain candidate was going to win the upcoming election, a random sample of
900 Americans were asked if they would vote for that candidate. The study showed that 46% were going
to vote for him. After the election was done we found out that 51% of the votes went to that candidate.
Which of the following statements is true? - ANSWER The number 46% is a sample statistic.
Statistics 221 BYU-I 57 correct solutions.
Which of the following variables is/are quantitative? - ANSWER The number of people in a randomly
selected classroom on campus.
The weight of a BYU-I student.
Students in an Introductory Statistics class at BYU-Idaho were studying prices of cold cereal at grocery
stores in Rexburg. To get a sample of cold cereal prices, they went to Albertson's and rolled a die to
decide which box from the left of the top shelf they would start on. They then recorded every 6th cereal
after the first, moving from left to right down the shelves, recording the name, size, and price of each
cereal in their sample. Is this study an experiment or an observational study, and why? - ANSWER An
observational study, because the students did not impose any treatment on the cereals.
Daniel was doing a statistical study. In which step of the statistical process is he engaged when he
creates a histogram of his data and calculates a sample mean? - ANSWER Describe the Data
In order to estimate the average weight of all adults in the state of Idaho, you randomly select 50 adults
from each county in Idaho. Use this information for all the parts.
Part 1: What type of sampling method was done here? - ANSWER Stratified Sample
In order to estimate the average weight of all adults in the state of Idaho, you randomly select 50 adults
from each county in Idaho. Use this information for all the parts.
Part 2: What is the population in your study above? - ANSWER The weights of all adults in the state of
Idaho.
You would like to test if females like math more than males do. You collect a sample of 100 males and
57 females. Among the 100 males, 32 say they like math. Among the females, 21 say they like math. Use
this information for all the parts.
Part 1: What is the null and alternative hypothesis? - ANSWER H0: P male=P female
HA: P male<P female
, Statistics 221 BYU-I 57 correct solutions.
You would like to test if females like math more than males do. You collect a sample of 100 males and
57 females. Among the 100 males, 32 say they like math. Among the females, 21 say they like math. Use
this information for all the parts.
What is the p-value for your test? - ANSWER .269
You would like to test if females like math more than males do. You collect a sample of 100 males and
57 females. Among the 100 males, 32 say they like math. Among the females, 21 say they like math. Use
this information for all the parts.
Part 3: Are the requirements for the above test satisfied? - ANSWER Yes, both and are larger than 10 for
both groups.
Tanker trucks are designed to carry huge quantities of gasoline from refineries to filling stations. A
factory that manufactures the tank of the trucks claims to manufacture tanks with a capacity of 8550
gallons of gasoline. The actual capacity of the tanks is normally distributed with mean gallons and
standard deviation gallons.
Part 1: What is the probability that a randomly chosen truck will have a capacity greater than 8528
gallons? - ANSWER .908
Tanker trucks are designed to carry huge quantities of gasoline from refineries to filling stations. A
factory that manufactures the tank of the trucks claims to manufacture tanks with a capacity of 8550
gallons of gasoline. The actual capacity of the tanks is normally distributed with mean gallons and
standard deviation gallons.
Part 2: Suppose that a simple random sample of tanks is selected and the sample mean capacity is found
to be 8550 gallons. What is the z-score corresponding to this sample mean? - ANSWER 2.336
Tanker trucks are designed to carry huge quantities of gasoline from refineries to filling stations. A
factory that manufactures the tank of the trucks claims to manufacture tanks with a capacity of 8550
gallons of gasoline. The actual capacity of the tanks is normally distributed with mean gallons and
standard deviation gallons.
Part 3: What is the probability that a sample of size 20 will have a mean between 8538 and 8550
gallons? - ANSWER .975
In order to decide if a certain candidate was going to win the upcoming election, a random sample of
900 Americans were asked if they would vote for that candidate. The study showed that 46% were going
to vote for him. After the election was done we found out that 51% of the votes went to that candidate.
Which of the following statements is true? - ANSWER The number 46% is a sample statistic.
