1.For the Density Curve Below, Which of the Following Is True?

Chapter 2

1.For the density curve below, which of the following is true?

A)The median is 0.5.

B)The median is larger than 0.5.

C)The density curve is skewed right.

D)The density curve is normal.

E)The density curve is symmetric.

2.Items produced by a manufacturing process are supposed to weigh 90 grams. The manufacturing process is such, however, that there is variability in the items produced and they do not all weigh exactly 90 grams. The distribution of weights can be approximated by a normal distribution with mean 90 grams and a standard deviation of 1 gram. What percentage of the items will either weigh less than 87 grams or more than 93 grams?

A)6%

B)94%

C)99.7%

D)0.3%

E)0.15%

3.Birthweights at a local hospital have a normal distribution with a mean of 110 oz. and a standard deviation of 15 oz. The proportion of infants with birthweights under 95 oz. is

A)0.500.

B)0.159.

C)0.341.

D)0.841.

E).025.

Use the following to answer question 4:

The following table presents data on wine consumption and death rate from heart attacks in 19 developed Western countries.

WINE CONSUMPTION AND HEART ATTACKS

AlcoholHeart diseaseAlcoholHeart disease

Countryfrom wineDeathsCountryfrom wineDeaths

Australia 2.5211Netherlands1.8167

Austria 3.9167New Zealand1.9266

Belgium2.9131Norway0.8227

Canada2.4191Spain6.586

Denmark2.9220Sweden1.6207

Finland0.8297Switzerland5.8115

France9.171United Kingdom1.3285

Iceland0.8211United States1.2199

Ireland0.7300West Germany2.7172

Italy7.9107

The distribution of heart disease death rates in these countries is close to this normal distribution:

4.From this normal curve, we see that the mean heart disease death rate per 100,000 people is about

A)60.

B)120.

C)190.

D)250.

E)400.

5.If the heights of 99.7% of American men are between 5'0" and 7'0", what is your estimate of the standard deviation of the height of American men?

A)1"

B)3"

C)4"

D)6"

E)12"

6.IQs among undergraduates at Mountain Tech are approximately normally distributed. The mean undergraduate IQ is 110. About 95% of undergraduates have IQs between 100 and 120. The standard deviation of these IQs is about

A)5.

B)10.

C)15.

D)20.

E)25.

7.The change in scales makes it hard to compare scores on the 1994 math SAT (mean 470, standard deviation 110) and the 1996 math SAT (mean 500, standard deviation 100). Jane took the SAT in 1994 and scored 500. Her sister Colleen took the SAT in 1996 and scored 520. Who did better on the exam, and how can you tell?

A)Colleen—she scored 20 points higher than Jane.

B)Colleen—her standard score is higher than Jane's.

C)Jane—her standard score is higher than Colleen's.

D)Jane—the standard deviation was bigger in 1994.

E)Can't tell from the information given.

8.A company produces ceramic floor tiles that are supposed to have a surface area of 16.0 square inches. Due to variability in the manufacturing process, the actual surface area has a normal distribution with a mean of 16.1 square inches and a standard deviation of 0.2 square inches. The proportion of tiles produced by the process with surface area less than 16.0 square inches is

A)0.1915.

B)0.4115.

C)0.3085.

D)0.6915.

E)0.3173.

9.The scores on a university examination are normally distributed with a mean of 62 and a standard deviation of 11. If the bottom 5% of students will fail the course, what is the lowest mark that a student can have and still be awarded passing grade?

A)62.

B)57.

C)44.

D)43.

E)40.

10.A soft-drink machine can be regulated so that it discharges an average of  oz. per cup. If the ounces of fill are normally distributed with a standard deviation of 0.4 oz., what value should  be set at so that 98% of 6-oz. cups will not overflow?

A)6.82

B)6.00

C)6.18

D)6.60

E)5.18

11.The five-number summary of the distribution of scores on a statistics exam is

0 26 31 36 50

316 students took the exam. The histogram of all 316 test scores was approximately normal. Thus the variance of test scores must be about

A)5.

B)8.

C)19.

D)64.

E)55.

12.Entomologist Heinz Kaefer has a colony of bongo spiders in his lab. There are 1000 adult spiders in the colony, and their weights are normally distributed with mean 11 grams and standard deviation 2 grams. About how many spiders are there in the colony which weigh more than 12 grams?

A)690

B)310

C)160

D)840

E)117

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