Unformatted text preview: MATH 230013, Spring 2011
Home work it 07 1) Based on previous studies, researchers believe that 6% of children are born with a gene that is
linked to a certain childhood disease. If the researchers test950 newborns for the presence of this
gene, would it be unlikely for them to find fewer than 2_5 children with the gene? Answer by
calculating the appropriate zscore. Yes,z=4.41 ’ . .1, ~73 é
(ﬂan3.335 [@1l%‘§‘ ‘" .m 2., :2; '.0o
0,z=' . P'_._____.———— 1)_A_ D) No, 2 = 6.59 norm 0'3 E)Yes,z=—6.59 Find the mean/standard error of the sampling distribution of the proportion.
/ ’23} candy company claims that its jelly bean mix contains 21% blue jelly beans. Suppose that the
3‘ handles are packaged at random in small bags containing about 400 jelly beans. Describe the
sam ling distributim model of the proportion of blue jelly beans in a bag. ean = 21%, starleard error = 2.0%
) mean = 21%; standard error = 0.8%
C) mean = 79%; standard error = 0.8%
D) mean = 79%; standard error = 2.0% E) There is not enough information to describe the distribution. Provide an appropriate response.
3) Which of the following are true:
I) the population distribution is approximately normal for large enough :1 II) the sampling distribution of 3; is approximately normal for any n
(fl13) regardless of the population distribution, the mean of the sampling distribution of ;equals " the population mean p
A) II only B) 111 only C) I only D) all of these 4) In one region, the September energy consumption levels for single—family homes had a mean of
1050 kWh and a standard deviation of 218 kWh. lf50 different homes are randomly selected, ﬁnd
the probability that their mean energy consumption level for September is greater than 1075 kWh. A) 0.0438 @02090 C) 0.2910 D) 0.4562 E) 0.4180 Find the mean/standard error of the sampling distribution of the proportion. 5) A realtor has been told that 43% of homeowners in a city prefer to have a finished basement. She
surveys a grOup of 300 homeowners randomly chosen from her client list. Describe the sampling
distribution model of the proportion of homeowners in this sample who prefer a finished
basement. A) mean = 57%; standard error = 1.4% B) mean ﬂ, standard error = 1.4% C) mean = 57%; standard error = 2.9% \ mean = ﬂ; standard error = 2.9%
3 There is not enough information to describe the distribution. 2) 3) 4) 5) = 4.32, ...
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