【官方】SAT数学每日一题附答案和解析(2018年2月26日)

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MathematicsStandard Multiple Choice

Read the following SAT test question and thenclick on a button to select your

answer.

A potato chip company produces the same numberof snack-sized bags of potato

chips every month. Amanager at the company randomly selects a sample of

snack-sized bags of potato chips to beweighed in a routine quality-assurance

check each month. The January sample had a meanweight of 0.95 ounces and a

margin of error of 0.06 ounces. The February sample had a meanweight of 0.98

ounces and a margin of error of 0.04 ounces. Based on these findings, which

ofthe following is an appropriate conclusion?

A.Most of the snack-sized bags of potato chips produced by the company in

January each had aweight of at least 0.95 ounces, while most of the snack-sized

bags of potato chips produced bythe company in February each had a weight of at

least 0.98 ounces.

B.The mean weight of all the snack-sized bags of potato chips produced by the

company inJanuary must have been 0.03 ounces more than the mean weight of all

the snack-sized bags ofpotato chips produced by the company in February.

C.The mean weight of all the snack-sized bags of potato chips produced by the

company inJanuary was 0.03 ounces less than the mean weight of all the

snack-sized bags of potato chipsproduced by the company in February.

D.The number of snack-sized bags of potato chips in the January sample was

less than thenumber of snack-sized bags of potato chips in the February

sample.

答案：D

解析：

Choice D is correct. Start by interpreting the resultsof each sample

individually before comparing thetwo.

The January sample had a mean weight of 0.95 ounces and a margin of error of

0.06 ounces. The February sample had a mean weight of 0.98 ounces and a margin

of error of 0.04 ounces.

This means that the average weight of a snack-sized bag of potato chips in

the January samplewas less than the average weight of a snack-sized bag of

potato chips in the February sampleand that the margin of error for the January

sample was larger than the margin of error forthe February sample.

The weight of the samples does not mean that the entire populations had the

same attributes, but the margin of error does give some insight about the sample

sizes.

Since the population of all snack-sized bags of potato chips was the same in

January as it wasin February, the larger margin of error in January indicates

that the January sample size wassmaller than the February sample size.