UNIT 1 & 6
UNIT 2
UNIT 3
UNIT 4
UNIT 5
100
The heights of adult women are approximately normally distributed about a mean of 65 inches with a standard deviation of 2 inches. If Rachael is at the 99th percentile in height for adult women, then her height in inches, is closest to
70
100
A researcher wishes to test a new drug developed to treat hypertension (high blood pressure). A group of 40 hypertensive men and 60 hypertensive women is to be used. The experimenter randomly assigns 20 of the men and 30 of the women to placebo and assigns the rest of the treatment. The major reason for seperate assignment for men and women is that ?
the new drug may affect men and women differently
100
A manufacturer makes lightbulbs and claims that their reliability is 98%. Reliability is defined to be the proportion of nondefective items that are produced over the long term. If the company's claim is correct, what is the expected number of nondefective lightbulbs in a random sample of 1,000 bulbs?
980
100
A safety group claims that the mean speed of drivers on a highway exceeds the posted speed limit of 65 miles per hour. To investigate the safety group's claim, which of the following statements is apporpriate? a) the null hypothesis is that the mean speed of drivers on this highway is less than 65 mph b) the null hypothesis is that the mean speed of drivers is greater than 65mph c) the alternative hypothesis is that the mean speed of drivers on this highway is greater than 65 mph d) the alternative hypothesis is that the mean speed of drivers on this highway is less than 65 mph e) the alternative hypothesis is that the mean speed of drivers on this highway is greater than or equal to 65 mph
c
100
A survey of 57 students was conducted to determine whether or not they held jobs outside of school. The two-way table above shows the numbers of students by employment status (job, no job) and class (juniors, seniors). Which of the following best describes the relationship between employment status and class? a) there appears to be no association, since the same number of juniors and seniors have jobs b) there appears to be no association, since close to half of the students have jobs c) there appears to be an association, since there are more seniors than juniors in the survey d) there appears to be an association, since the proportion of juniors having jobs is much larger than ther proportion of seniors having jobs e) a measure of association cannot be determined from these data
d)
200
Gina's doctor told her that the standard score (z-score) for her systolic blood pressure, as compared to the blood pressure of other women her age, is 1.50. What is the best interpretation of this standardized score?
Gina's systolic blood pressure is 1.50 standard deviations above the average systolic blood pressure of women her age
200
Which of the following can be used to show a cause-and-effect relationship between two variables?
a controlled experiment
200
A fair coin is to be flipped 5 times. The first 4 flips land "heads up". What is the probability of 'heads' the next (5th) flip of the coin?
1/2
200
USA Today reported that speed skate Bonnie Blair had "won the USA's heart," according to a USA Today/CNN/ Gallup Poll conducted on the final Thursday of the 1994 Winter Olympics. When asked who was the hero of the Olympics, 65 percent of the respondents chose Blair, who won five gold medals. The poll of 615 adults, done by telephone, had a margin of error of 4 percent. Which of the following statements best describes what is meant by the 4 percent margin of error? a) About 4 percent of adults were expected to change their minds between the time of the poll and its publication in USA Today b) About 4 percent of adults did not have telephones c) About 4 percent of the 615 adults polled refused to answer d) Not all of the 615 adults knew anything about the Olympics e) The difference between the sample percentage and the population percentage is likely to be less than 4 percent
e)
200
a random sample of the costs of repair jobs at a large muffler repair shop produces a mean of $127.95 and a standard deviation of $24.03. If the size of this sample is 40, what is an approximate 90 percent confidence interval for the avg cost of a repair at this repair shop
$127.95 plus or minus $6.25
300
The statistics below provide a summary of the distribution of height, in inches, for a simple random sample of 200 young children mean: 46 inches median: 45 inches standard deviation: 3 inches first quarter: 43 inches third quarter: 48 inches About 100 children in the sample have heights that are...
between 43 and 48 inches
300
To check the effect of cold temp. on the elasticity of two brands of rubber bands, one box of Brand A and one box of Brand B rubber bands are tested. Ten Brands from the Brand A box are placed in a freezer for two hours and ten bands from the Brand B box are kept at room temp. The amount of stretch before breakage is measure on each rubber band, and the mean for the cold bands is compared to the mean for the others Is this a good experimental design?
No, becuase temp is confounded with brand
300
Let X represent a random variable whose distribution is normal, with a mean of 100 and a standard deviation of 10. Which of the following is equivalent to P(X>115)? a) P(X<115) b) P(X greater than or equal to 115) c) P(X<85) d) P (85
c) P(X<85)
300
Which of the following is a criterion for choosing a t-test rather than z-test when making an inference about the mean of a population? a) the standard deviation of the population is unknown b) the mean of the population is unknown c) the sample may not have been a simple random sample d) the population is not normally distributed e) the sample size is less than 100
a)
300
A survey was conducted to determine what percentage of college seniors would have chosen to attend a different college if they had known then what they know now. In a random sample of 100 seniors, 34% indiciated that they would have attended a different college. A 90 percent confidence interval for the percentage of all seniors who would have attended a different college is?
26.2% to 42.2%
400
A delivery service places packages into large containers before flying them across the country. These filled containers vary greatly in their weight. Suppose the delivery service's airplanes always transport two such containers on each flight. The two containers are chosen so their combined weight is close to, but does not exceed, a specified weight limit. A random sample of flights with these containers is taken, and the weight of each of the two containers on each selected flight is recorded. The weights of the two containers on the same flight will have what correlation?
a negative correlation
400
Automobile brake pads are either metallic or nonmetallic. An experiement is to be conducted to be determined whether the stopping distance is the same for both types of brake pads. In previous studies, it was determined that car size (small, medium, large) is associated with stopping distance, but car type (sedan, wagon, coupe) is not associated with stopping distance. This experiment would best be done how?
By blocking on car size
400
The distribution of diameters of a particular variety of oranges is approximately normal with a standard deviation of 0.3 inch. How does the diameter of an orange at the 67th percentile compare with the mean diameter?
0.132 inch above the mean
400
The distribution of the weights of loaves of bread from a certain bakery follows approximately a normal distribution. Based on a very large sample, it was found that 10 percent of the loaves weighed less than 15.34 ounces, and 20 percent of the loaves weighed more than 16.31 ounces. What are the mean and standard deviation of the distribution of the weights of the loaves of bread? a) mean= 15.82, SD= 0.48 b) mean= 15.82, SD= 0.69 c) mean= 15.87, SD= 0.50 d) mean= 15.93, SD= 0.46 e) mean= 16.00, SD= 0.50
d
400
The process of producing pain-reliever tables yields tablets with varying amounts of the active ingredient. It is claimed that the avg amount of active ingredient per tablet is at least 200 milligrams. The Consumer Watchdog Bureau tests a random sample of 70 tablets. The mean content of the active ingredient for this sample is 194.3 milligrams, while the standard deviation is 21 milligrams. What is the approximate p-value for the appropriate test?
0.012
500
if two variables are positively associated, then what happens?
large values of one variable are associated with larger values of the other
500
Which of the following is NOT a characteristic of stratified random sampling? a) random sampling is part of the sampling procedure b) the population is divided into groups of units that are similiar on some characteristics c) the strata are based on facts known before the sample is selected d) each individual unit in the popular belongs to one and only one strata e) Every possible subset of population, of the desired sample size, has an equal chance of being selected
E
500
Circuit boards are assembled by selecting 4 computer chips at random from a large batch of chips. In this batch of chips, 90 percent of the chips are acceptable. Let X denote the number of acceptable chips out of a sample of 4 chips from this batch. What is the least probable value of X?
0
500
When performing a test of significance about a population mean, a t-distribution, instead of a normal distribution, is often utilized. Which is the most appropriate explanation for this? a) the sample size is not large enough to assume that the population is normal b) the sample does not follow a normal distribution c) there is an increase in the variability of the test statistic due to estimation of the population d) the sample standard deviation is unknown e) the population standard deviation is too large
c)
500
A 95 percent confidence interval of the form p-hat plus or minue E will be used to obtain an estimate for an unknown population proportion p. If p-hat is the sample proportion and E is the margin of error, which of the following is the smallest sample size that will guarantee a margin of error of at most 0.08?
175
M
e
n
u