Show:
Random Variables
Probability
Confidence Intervals
Hypothesis Testing
Just for Fun
100
Seed depot advertises that 85% of its flower seeds will germinate (grow). Suppose that the company's claim is true. Judy buys a packet with 20 flower seeds from Seed Depot and plans them in her garden. Let X=the number of seeds that germinate. This is known as a ________ distribution.
What is a binomial distribution?
100
A fair coin is tossed 3 times. _____ is the probability of tossing more heads than tails.
What is 1/2?
100
____ is the critical value t* to be used with the following information: A 95% confidence interval with n=10 observations.
What is 2.262
100
Simon reads a newspaper report claiming that 12% of people in the U.S. are left-handed. He wonders if 12% of the students at his large high school are left handed. He chooses an SRS of 100 students and records whether each student is right or left handed. _________ is the null and alternative hypothesis for Simon's study.
What is H(0): p=.12, H(a): P not equal to .12
100
________ was the second drummer for the Beatles.
Who is Ringo Starr?
200
Exactly 10% of the students in a school are left handed. Select students at random from the school, one at a time, until you find one who is left-handed. Let V=the number of students chosen. This is known as a _______ distribution.
What is a geometric distribution?
200
All human blood can be typed as one of O, A, B or AB, but the distribution of types varies a bit with race. Here is the distribution of the blood type of a randomly chosen black American. O: .49; A: .27; B: .2; AB:____.
What is .04?
200
A researcher plans to use a random sample of n=500 families to estimate the mean monthly family income for a large population. a 99% confidence interval would be _______ than a 90% confidence interval.
What is wider? (it would have a smaller risk of being incorrect).
200
A poll report on a national survey of 1028 teens revealed that 72% of teens said they rarely or never argue with their friends. Joe wonders whether this national result would be true in his large high school, so he surveys a random sample of 150 students. In his survey 96 said they rarely or never argue with their friends. ______ is the test-statistic for this study.
What is z=-2.18
200
Georgia is famous for this kind of fruit.
What is peaches
300
An opinion poll calls residential telephone numbers at random, only 20% of the calls reach a live person. You watch the random digit dialing machine make 15 calls. Let X=the number of calls that reach a live person. Find and interpret the mean of X.
What is 3? You would expect to reach a live person in an average of 3 phone calls when making 15 phone calls.
300
The two-way table (#1) describes the members of the U.S. senate in a recent year. Suppose we select a senator at random. Consider events D: is a democrat, and F: is a female. _____ is P(D|F).
What is .7647? (76.47% of the females are democrats).
300
Here are some of the mpg values for a random sample of 20 records from a specific vehicle: 15.8, 13.6, 15.6, 19.1, 22.4, 15.6, 22.5, 17.2, 19.4, 22.6, 19.4, 18.0, 14.6, 18.7, 21.0, 14.8, 22.6, 21.5, 14.3, 20.9. Construct and interpret a 95% confidence interval for the mean mpg for this vehicle.
What is (17.02, 19.94): We are 95% confident that the interval from 17.02 to 19.94 captures the true mean miles per gallon for this car.
300
Cola makers test new recipes for loss of sweetness during storage. Trained tasters rate the sweetness before and after storage. Here are the sweetness losses (before-after) found by the tasters for a random sample of 10 batches of a new cola recipe: 2.0, .4, .7, 2.0, -.4, 2.2, -1.3, 1.2, 1.1, 2.3. Are these data good enough evidence that the cola lost sweetness?
What is Since our p-value (.0122) is less than .05, we reject H(0)--there seems to be an average loss of sweetness for this cola.
300
______ is the only number between 1-100 that is spelled out alphabetically
What is forty
400
To start her old mower, Rita has to pull a cord and hope for some luck. On any particular pull, the mower has 20% chance of starting. _______ is the probability of it starting in exactly three pulls.
What is .128?
400
A recent study suggests that 85% of college students have posted a profile on Facebook, 54% use MySpace regularly, and 42% do both. Suppose we select a college student at random and learn that the student has a Facebook profile. ______ is the probability that the students uses MySpace regularly.
What is .4941?
400
One large university asked a random sample of 1296 students who had a summer job how much they earned. They separated the responses based on gender (see table 3). Construct and interpret a 90% confidence interval for the difference between the mean summer earnings of male and Female students at the university.
What is we are 90% confident that the interval from 413.56 to 634.70 captures the actual difference in mean summer earnings of male and female students.
400
Researchers equipped random samples of 56 female and 56 male students from a large university with a small device that secretly records sound for a random 30 seconds during each 12.5 minute period over two days. Then they recorded the number of words spoken by each subject during each recording period and, from this, estimated ow many words per day each subject speaks. The female estimates ah a mean of 16,177 words per day with a standard deviation of 7520 words per day. For the male estimates, the mean was 16,569 and the standard deviation was 9108. Do these data provide convincing evidence of a difference in average number of words spoken?
What is Since our p-value (.805) is greater than .05, we fail to reject H(0). We do not have convincing evidence that male and female students speak a different number of words per day.
400
_________ wrote the lyrics to the Star-Spangled Banner
Who is Francis Scott Key
500
Exactly 10% of the students in a school are left handed. Select 15 students at random from the school, one at a time. Let V=the number of students who are left handed. _____=P(V is greater than or equal to 4).
What is .0556?
500
Suppose that each child born is equally likely to be a boy or a girl and that the genders of successive children are independent. If we let BG mean that the older child is a boy and the younger child is a girl, then each of the combinations BB, BG, GB, GG has the probability .25. Assume Ashley has two children and at least one of them is a boy. ____ is the probability that she has two boys.
What is .333?
500
Sixteen volunteers with an initial BAC of 0 drank a randomly assigned number of cans of beer. Thirty minutes later, a plice officer measured their BAC. Use the computer output (see table 2). Find and interpret a 99% confidence interval for the slope of the true regression line.
What is We are 99% confident that the interval from .011 to .025 captures the true slope of the population regression line for predicting BAC level from the number of beers consumed.
500
The distribution of ethnic background of New York City is as follows: Hispanic 28%, Back 24%, White 35%, Asian 12% other 1%. The manager of a housing complex wonders whether the distribution by race is the complex is consistent with the population distribution. She records the following data from a sample of 800 residents: Hispanic 212, Black 202, White 270, Asian 94, Other 22. Are these data significantly different from the city's distribution?
What is Since our p-value is .00003 (less than .05), we reject H(0) and conclude that the residents do not follow the population distribution of the city.
500
_______ is the minimum number of members a band must have to be considered a "big band"
What is 10