A public radio station held a fund-raiser. The table below summarizes the donor category and method of donation.
Donor Category | |||
---|---|---|---|
Supporter | Patron | ||
Method of | Phone calls | 400 | 672 |
Donation | Online | 1200 | 2016 |
To the nearest thousandth, find the probability that a randomly selected donor was categorized as a supporter, given that the donation was made online.
Do these data indicate that being a supporter is independent of donating online? Justify your answer.
Calculate the probability of being a supporter given the donation was made online.
Determine if being a supporter is independent of donating online.
In watching auditions for lead singer in a band, Liem became curious as to whether there is an association between how animated the lead singer is and the amount of applause from the audience. He decided to watch each singer and rate the singer on a scale of 1 to 5 , where 1 is the least animated and 5 is the most animated. He did this for all 5 nights of auditions and found that the more animated singers did receive louder applause. The study Liem conducted would be best described as
Describe how a controlled experiment can be created to examine the effect of ingredient in a toothpaste.
Describe the steps to create a controlled experiment.
The scores on a mathematics college-entry exam are normally distributed with a mean of 68 and standard deviation 7.2. Students scoring higher than one standard deviation above the mean will not be enrolled in the mathematics tutoring program. How many of the 750 incoming students can be expected to be enrolled in the tutoring program?
A population is normally distributed with a mean of 23 and a standard deviation of 1.2. The percentage of the population that falls below 21 , to the nearest hundredth, is
Chuck's Trucking Company has decided to initiate an Employee of the Month program. To determine the recipient, they put the following sign on the back of each truck.
The driver who receives the highest number of positive comments will win the recognition. Explain one statistical bias in this data collection method.
Explain one statistical bias in this data collection method.
A random sample of 100 people that would best estimate the proportion of all registered voters in a district who support improvements to the high school football field should be drawn from registered voters in the district at a
A public opinion poll was conducted on behalf of Mayor Ortega's reelection campaign shortly before the election. 264 out of 550 likely voters said they would vote for Mayor Ortega; the rest said they would vote for his opponent.
Which statement is least appropriate to make, according to the results of the poll?
Robin flips a coin 100 times. It lands heads up 43 times, and she wonders if the coin is unfair. She runs a computer simulation of 750 samples of 100 fair coin flips. The output of the proportion of heads is shown below.
Do the results of the simulation provide strong evidence that Robin's coin is unfair? Explain your answer.
Do the results of the simulation provide strong evidence that Robin's coin is unfair? Explain your answer.
Two classes of students were entered into an experiment to see whether using an interactive whiteboard leads to better grades. It was observed that the mean grade of students in the class with the interactive whiteboard was 0.6 points higher than the class without it. To determine if the observed difference is statistically significant, the classes were rerandomized 5000 times to study these random differences in the mean grades. The output of the simulation is summarized in the histogram below.
Determine an interval containing the middle 95% of the simulation results. Round your answer to the nearest hundredth.
Does the interval indicate that the difference between the classes' grades is significant? Explain.
Determine an interval containing the middle 95% of the simulation results.
Does the interval indicate that the difference between the classes' grades is significant? Explain.