How confident are you?
Hypothetically Speaking
Are y'all correlated?
Further testing is needed
100
In a survey of 73,901 college graduates, 23,991 obtained a postgraduate degree. Construct a 90% confidence interval to estimate the population proportion. (round to the thousandths place)
What is (0.322, 0.327)?
100
The statement below represents a claim. Write its complement and state which is H_0 and which is H_a .
sigma > 1.9
What is H_0: sigma <=1.9 , H_a: sigma>1.9 ?
100
For the dataset provided calculate the sample correlation coefficient, r, and describe the type of correlation.
The numbers of pass attempts and passing yards for seven professional quarterbacks for a recent regular season.
What is r = 0.937 , strong positive linear correlation ?
100
Two conditions that must be met in order to run the chi^2 goodness-of-fit and independence tests.
What is the observed frequencies must come from a random sample and each expected frequency must be greater than or equal to 5?
200
From a random sample of 36 business days during the year 2020, the mean closing price of Apple stock was $97.17. Assume the population standard deviation is $21.77. Construct a 95% confidence interval to estimate the population. (round to the nearest penny)
What is (90.06, 104.28)?
200
A travel analyst claims the mean daily base price for renting a full-size or less expensive vehicle in Vancouver, British Columbia, is more than $86. You want to test this claim. In a random sample of 40 full-size or less expensive vehicles available to rent in Vancouver, British Columbia, the mean daily base price is $93.23. Assume the population standard deviation is $28.90. At alpha = 0.10 , do you have enough evidence to support the analyst’s claim?
In your answer provide the following:
a) Identify the claim and state H_0 and H_a
b) Decide whether to reject or fail to reject the null hypothesis.
c) Interpret the decision in the context of the original claim.
H_0:mu<=86
H_a:mu>86 (claim)
p = 0.057
p<alpha -> reject H_0
There is enough evidence to support the claim.
200
For the dataset provided calculate the sample correlation coefficient, r, and describe the type of correlation.
The numbers of wildland fires (in thousands) and wildland acres burned (in millions) in the United States for eight years.
What is r = 0.494 , weak positive linear correlation ?
200
A researcher claims that the ages of people who go to the movies at least once a year are distributed as shown in the figure. You randomly select 1000 people who went to the movies at least once in 2020 and record the age of each. The table shows the results. Calculate the expected frequencies of each age group.
What is
300
In a random sample of eight cell phones, the mean full retail price was $526.50 and the standard deviation was $184.00. Construct a 95% confidence interval to estimate the population mean. (round to the hundredths place)
What is (372.67, 680.33)?
300
A nonprofit consumer organization says that less than 25% of the televisions the organization rated in a recent year have an overall score of 70 or more. In a random sample of 35 televisions the organization rated in a recent year, 23% have an overall score of 70 or more. At alpha=0.05 , can you support the organization’s claim?
In your answer provide the following:
a) Identify the claim and state H_0 and H_a
b) Decide whether to reject or fail to reject the null hypothesis.
c) Interpret the decision in the context of the original claim.
H_0:p >= 0.25
H_a:p < 0.25 (claim)
p = 0.385
p > alpha ->
fail to reject H_0
There is not enough evidence to support the claim.
300
The average numbers (in thousands) of milk cows and the amounts (in billions of pounds) of milk produced in the United States for eight years is shown in the table below. Find the regression line.
What is haty = 0.097x -695.161 ?
300
A researcher claims that the numbers of cups of coffee U.S. adults drink per day are distributed as shown in the figure. You randomly select 1600 U.S. adults and ask them how many cups of coffee they drink per day. The table shows the results. At alpha=0.05 , test the researcher’s claim.
H_0: The number of cups of coffee per day is distributed as shown in the pie chart. (claim)
H_a: The number of cups of coffee per day is not distributed as shown in the pie chart.
p = 0.108
p > alpha therefore we fail to reject H_0
There is not enough evidence to reject the claim that the distribution of cups per day matches the pie chart.
400
You're interested in collecting data to find average driving distances (in miles) to work of a certain population of people. Assume the population standard deviation is 8 miles. Determine the minimum sample size required to be 99% confident that the sample mean driving distance to work is within 2 miles of the population mean driving distance to work.
What is n = 107 people?
400
A government agency reports that the mean amount of earnings for full-time workers ages 18 to 24 with a bachelor’s degree in a recent year is $52,133. In a random sample of 15 full-time workers ages 18 to 24 with a bachelor’s degree, the mean amount of earnings is $48,400 and the standard deviation is $6679. At alpha = 0.05 , is there enough evidence to reject the claim? Assume the population is normally distributed.
In your answer provide the following:
a) Identify the claim and state H_0 and H_a
b) Decide whether to reject or fail to reject the null hypothesis.
c) Interpret the decision in the context of the original claim.
H_0:mu = 52,133 (claim)
H_a:mu != 52,133
p = 0.048
p<alpha -> reject H_0
There is enough evidence to reject the claim.
400
The ages (in years) and the numbers of hours of sleep in one night for seven adults is shown in the table below. Predict the number of hours a 50 year old adult will sleep in one night.
What is 6.15 hours?
Regression line used:
haty = -0.086x +10.450
400
The contingency table shows the results of a random sample of former smokers by their gender and the number of times they tried to quit smoking before they were habit-free. At alpha=0.05 , can you conclude that the number of times they tried to quit before they were habit-free is related to gender?
H_0: The variables of gender and the number of times one tried to quit smoking are independent.
H_a: The variables of gender and the number of times one tried to quit smoking are dependent. (claim)
p = 0.999
p > alpha therefore we fail to reject H_0
There is not enough evidence to support the claim that gender and the number of attempts to quit are related.