qmb 3250 exam 1
What is a response variable? - ANSwhat the study is trying to determine
To look at the relationship between Serum 25(OD)D levels and location(urban/rural), what type
of graph might you use? - ANSboxplot
A histogram is a graphical display to show _________ . - ANSthe outcomes of a quantitative
variable.
What is the primary purpose of the 95% confidence interval for μ2-μ1 ? - ANSTo estimate the
difference between the mean of population 1 and population 2. The Confidence Interval for two
independent means is interested in estimating the difference between the parameters.
In significance testing, what does α represent? - ANSThe probability of a Type I error
what type of statistical test should be used to determine are older people more likely than
younger people to consider purchasing a hybrid vehicle? - ANSComparing two independent
proportions
categorical data - two groups
what type of statistical test should be used to determine what is the typical price of a used
Toyota Prius manufactured in 2011? - ANSOne Mean
quantitative data - one group
what type of statistical test should be used to determine if there is a difference in used car price
for a Toyota Prius with 2 or 4 cylinders? - ANSComparing two independent means
quantitative data - two groups
what type of statistical test should be used to determine if there is a significant difference in gas
mileage for a Toyota Prius driven 100 miles in the mountains versus along a flat coastline? Ten
drivers determine their gas mileage for the same stretch of roads in the mountains and along
the flat coastline. - ANSComparing means of dependent samples
quantitative data - paired responses
what type of statistical test should be used to determine what proportion of people purchase a
hybrid cars after they have been given a test drive? - ANSOne Proportion
categorical data - one group
In the past the average life span for a flashlight battery has been 10 hours. However, the
production line has been improved in the past six months. The manufacturer wants to determine
, if the lifetime of the battery has improved. The manufacturer tested the lifetimes of 25 batteries.
What would be the appropriate hypothesis to test this claim? - ANSHo: μ =10 versus Ha: μ >10
In the past the average life span for a flashlight battery has been 10 hours. However, the
production line has been improved in the past six months. The manufacturer wants to determine
if the lifetime of the battery has improved. The manufacturer tested the lifetimes of 25 batteries.
What is the parameter being estimated? - ANSμ = population mean lifetime of the battery
For the hypothesis Ho: μ1-μ2=0 versus Ha: μ1-μ2≠0, the p-value equals 0.021. Let α = 0.05.
What decision would be made here? If an error is made here, what type of error would it be? -
ANSReject Ho
Rule: p-value ≤ α Reject Ho The p-value = 0.021 < α = 0.05
Type I error since we rejected Ho, the only type of error that we could make if we made an error
would be Type I error. The definition of a type 1 error is the error that occurs when we reject Ho
when Ho is true.
type 1 error - ANSis the error that occurs when we reject Ho when Ho is true
For a significance test for the population proportion with significance level equal to 0.10 and
p-value equal to 0.06, what would be the correct decision? - ANSReject Ho
Rule: p-value ≤ α Reject Ho - Since the p-value is less than alpha, we would reject Ho. If the
p-value was larger than alpha, we would have failed to reject Ho.
true or false: The p-value is the probability that the null hypothesis is true. - ANSfalse
The definition of the p-value is - ANSthe probability that we see a test statistic this extreme or
more if the null hypothesis is true.
Which of the following is not correct? The standard deviation of a statistic describes - ANSThe
standard deviation of the sample data measurements
The standard deviation of a statistics refers to - ANShow much the statistics changes.
is "The probability that p is between 0.3961 and 0.4823 is 0.95." a correct interpretation? -
ANSno, you can't state specific values of the confidence interval and use specific values in the
confidence interval. You can only speak of probability in the general sense. For example, "The
probability that the true proportion is in a 95% confidence interval is 0.95" is correct.
is "We are 95% confident that the true proportion of Caucasian Millennials who agree that
college is necessary to be successful in today's work world is between 0.3961 and 0.4823." a
correct interpretation? - ANSyes
For the sampling distribution of the sample mean, what happens to the standard deviation as
the sample size increases? - ANSIt decreases
What is a response variable? - ANSwhat the study is trying to determine
To look at the relationship between Serum 25(OD)D levels and location(urban/rural), what type
of graph might you use? - ANSboxplot
A histogram is a graphical display to show _________ . - ANSthe outcomes of a quantitative
variable.
What is the primary purpose of the 95% confidence interval for μ2-μ1 ? - ANSTo estimate the
difference between the mean of population 1 and population 2. The Confidence Interval for two
independent means is interested in estimating the difference between the parameters.
In significance testing, what does α represent? - ANSThe probability of a Type I error
what type of statistical test should be used to determine are older people more likely than
younger people to consider purchasing a hybrid vehicle? - ANSComparing two independent
proportions
categorical data - two groups
what type of statistical test should be used to determine what is the typical price of a used
Toyota Prius manufactured in 2011? - ANSOne Mean
quantitative data - one group
what type of statistical test should be used to determine if there is a difference in used car price
for a Toyota Prius with 2 or 4 cylinders? - ANSComparing two independent means
quantitative data - two groups
what type of statistical test should be used to determine if there is a significant difference in gas
mileage for a Toyota Prius driven 100 miles in the mountains versus along a flat coastline? Ten
drivers determine their gas mileage for the same stretch of roads in the mountains and along
the flat coastline. - ANSComparing means of dependent samples
quantitative data - paired responses
what type of statistical test should be used to determine what proportion of people purchase a
hybrid cars after they have been given a test drive? - ANSOne Proportion
categorical data - one group
In the past the average life span for a flashlight battery has been 10 hours. However, the
production line has been improved in the past six months. The manufacturer wants to determine
, if the lifetime of the battery has improved. The manufacturer tested the lifetimes of 25 batteries.
What would be the appropriate hypothesis to test this claim? - ANSHo: μ =10 versus Ha: μ >10
In the past the average life span for a flashlight battery has been 10 hours. However, the
production line has been improved in the past six months. The manufacturer wants to determine
if the lifetime of the battery has improved. The manufacturer tested the lifetimes of 25 batteries.
What is the parameter being estimated? - ANSμ = population mean lifetime of the battery
For the hypothesis Ho: μ1-μ2=0 versus Ha: μ1-μ2≠0, the p-value equals 0.021. Let α = 0.05.
What decision would be made here? If an error is made here, what type of error would it be? -
ANSReject Ho
Rule: p-value ≤ α Reject Ho The p-value = 0.021 < α = 0.05
Type I error since we rejected Ho, the only type of error that we could make if we made an error
would be Type I error. The definition of a type 1 error is the error that occurs when we reject Ho
when Ho is true.
type 1 error - ANSis the error that occurs when we reject Ho when Ho is true
For a significance test for the population proportion with significance level equal to 0.10 and
p-value equal to 0.06, what would be the correct decision? - ANSReject Ho
Rule: p-value ≤ α Reject Ho - Since the p-value is less than alpha, we would reject Ho. If the
p-value was larger than alpha, we would have failed to reject Ho.
true or false: The p-value is the probability that the null hypothesis is true. - ANSfalse
The definition of the p-value is - ANSthe probability that we see a test statistic this extreme or
more if the null hypothesis is true.
Which of the following is not correct? The standard deviation of a statistic describes - ANSThe
standard deviation of the sample data measurements
The standard deviation of a statistics refers to - ANShow much the statistics changes.
is "The probability that p is between 0.3961 and 0.4823 is 0.95." a correct interpretation? -
ANSno, you can't state specific values of the confidence interval and use specific values in the
confidence interval. You can only speak of probability in the general sense. For example, "The
probability that the true proportion is in a 95% confidence interval is 0.95" is correct.
is "We are 95% confident that the true proportion of Caucasian Millennials who agree that
college is necessary to be successful in today's work world is between 0.3961 and 0.4823." a
correct interpretation? - ANSyes
For the sampling distribution of the sample mean, what happens to the standard deviation as
the sample size increases? - ANSIt decreases
