USA Today reported that speed skater 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 c
The difference between the sample percentage and the population percentage is likely to be less than 4 percent.
An automobile manufacturer claims that the average gas mileage of a new model is 35 miles per gallon (mpg). A consumer group is skeptical of this claim and thinks the manufacturer may be overstating the average gas mileage. If � represents the true averag
H?: �= 35 mpg
H?: u< 35 mpg
A magazine has 1,620,000 subscribers, of whom 640,000 are women and 980,000 are men. Thirty percent ofthe women read the advertisements in the magazine and 50 percent of the men read the advertisements in the magazine. A random sample of 100 subscribers i
42
A manufacturer makes lightbulbs and claims that their reliability is 98 percent. 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 nond
980
When a virus is placed on a tobacco leaf, small lesions appear on the leaf. To compare the mean number of lesions produced by two different strains of virus, one strain is applied to half of each of 8 tobacco leaves, and the other strain is applied to the
7
Which of the following is a criterion for choosing a t-test rather than a z-test when making an inference about the mean of a population?
The standard deviation of the population is unknown
A certain county has 1,000 farms. Corn is grown on 100 of these farms but on none of the others. In order to estimate the total farm acreage of corn for the county, two plans are proposed.
Plan I: (a) Sample 20 farms at random. (b) Estimate the mean acrea
Choose plan II over plan I.
Which of the following can be used to show a cause-and-effect relationship between two variables?
A controlled experiment.
To check the effect of cold temperature 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 bands from the Brand A box are placed in a freezer for two hours and ten bands from the Brand B
No, because temperature is confounded with brand.
The boxplots above (picture not included but Set A is a little larger going from about 21-39 and a line in the middle at 30....and Set B goes from about 22-38 and a line a little left of middle at 29) summarize two data sets, A and B. Which of the followi
III only-- which is "The data in Set A have a larger range that the data in Set B
Ths XYZ Office Supplies Company sells calculators in bulk at wholesale prices, as well as individually at retail prices. Next year's sales depend on market conditions, but executives use probability to find estimates of sales for the coming year. The foll
$220,700
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
Joe and Matthew plan to visit a bookstore. Based on their previous visits to this bookstore, the probability distributions of the number of books they will buy are given below.....
Number of books Joe will buy/Probability...... 0/.50 1/.25 2/.25
Number of
0.1250
Chart:
Juniors / Job 13/ No Job 5/ Total 18......
Seniors/ Job 13/ No Job 26/ Total 39.....
Total/ Job 26/ No Job 31/ Total 57
A survey of 57 students was conducted to determine whether or not they held jobs outside of school. The two-way table above show
There appears to be an association, since the proportion of juniors having jobs is much larger than the proportion of seniors having jobs.
Which of the following is the best estimate of the standard deviation of the distribution showin in the figure above? (figure looks like a mountain and starts at about 20 and ends at about 80 but diagram only shows the numbers underneath of 30-70 in inter
10
Ten students were randomly selected from a high school to take part in a program designed to raise their reading comprehension. Each student took a test before and after completing the program. The mean of the differences between the score after the progr
For any �(A) and �(B) with 9<(�(A)-�(B)<23, the sample result is quite likely
Gina's doctor told her that the standardized score (z-score) for her systolic blood pressure, as compared to the blood pressure of other women her age, is 1.50. Which of the following 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
The Physicians' Health Study, a large medical experiment involving 22,000 male physicians, attemped to determine whether aspirin could help prevent heart attacks. In this study, one group of about 11,000 physicians took an aspirin every other day, while a
I,II, and III....which are "The study included only physicians, and different results may occur in individuals in other occupations"...."The study included only males and there may be different results for females"..."Although taking aspirin may be helpfu
Every Thursday, Matt and Dave's Video Venture has "roll-the dice" day. A customer may choose to roll two fair dice and rent a second movie for an amount (in cents) equal to the numbers uppermost on the dice with the larger number first. For example, if th
$9.40
Every Thursday, Matt and Dave's Video Venture has "roll-the dice" day. A customer may choose to roll two fair dice and rent a second movie for an amount (in cents) equal to the numbers uppermost on the dice with the larger number first. For example, if th
0.14
A company wanted to determine the health care costs of its employees. A sample of 25 employees were interviewed and their medical expenses for the previous year were determined. Later the company discovered that the highest medical expense in the sample w
Median
The back-to-back stem-and-leaf plot below (can't include the actual plot) gives the percentage of students who dropped out of school at each of the 49 high schools in a large metropolitan school district.
Which of the following statements is NOT justified
The drop-out rate decreased in each of the 49 high schools between the 1989-1990 and 1992-1993 school years
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
0
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, which of the following is an approximate 90 percent confidence interval for the ave
$127.95(+?) $6.25
At a college the scores on the chemistry final exam are approximately normally distributed, with a mean of 75 and a standard deviation of 12. The scores ont eh calculus final are also approximately normally distributed, with a mean of 80 and a standard de
The student did equally well in each course.
A fair coin is flipped 10 times and the number of heads is counted. The procedure of 10 coin flips is repeated 100 times and the results are place in a frequency table. Which of the frequency tables below is most likely to contain the results from these 1
chart shows number of heads 0-10 and then the following frequencies in order....
0/0/6/9/22/24/18/12/7/2/0 (REMEMBER two zeros at top and just 1 zero at end)
The student government at a high school wants to conduct a survey of student opinion. It wants to begin with a simple random sample of 60 students. Which of the following survey methods will produce a simple random sample?
Number the students in the official school roster. Use a table or random numbers to choose 60 students from this roster for the survey.
There is a linear relationship between the number of chirps made by the striped ground cricket and the air temperature. A least squares fit of some data collected by a biologist gives the model.... y=25.2 + 3.3x 9<x<25, where x is the number of chirps per
16.5�F
In a test of the null hypothesis H?: �=10 against the alternative hypothesis H(a): �>10, a sample from a normal population produces a mean of 13.4. The z-score for the sample is 2.12 and the p-value is 0.017. Based on these statistics, which of the follow
There is reason to conclude that �>10.
For which of the following distributions is the mean greater that the median?
answer is a picture....description of picture as follows: sloped line going down from y-axis to x-axis
The equation of the least squares regression line fror the points on the scatterplot above (could not include pictures but points are at 1,1/4,2/3,5/4,7/6,4/7,7) y=1.3 + 0.73x/ What is the residual for the point (4,7)?
2.78
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 wighed les than 15.34 ounces, and 20 percent of the loaves weigh
�=15.93, ?=0.46
A 95 percent confidence interval of the form p(plus or minus)E will be used to obtain an estimate for an unknown population proportion p. If p is the sample proportion and E is the margin of error, which of the following is the smallest sample size that w
175
The process of producing pain-reliever tablets yields tables with varying amounts of the active ingredient. It is claimed that the average amount of active ingredient per tablet is at least 200 milligrams. The Consumer Watchdog Bureau tests a random sampl
0.012
A survey was conducted to determine what percentage of college seniors would have chosen to attend a different college if they had known what they know now. In a random sample of 100 seniors, 34 percent indicated that they would have attended a different
26.2% tp 41.8%