Question

Part A:

An analysis of 97 Wall Street traders showed that 20 of their stock picks beat the market average. What is the estimate of the population proportion? What is the standard error of this estimate?

	1) The true population proportion is needed to calculate this.
	2) Estimate of proportion: 0.794, Standard error: 0.0042.
	3) Estimate of proportion: 0.206, Standard error: 0.0042.
	4) Estimate of proportion: 0.206, Standard error: 0.0411.
	5) Estimate of proportion: 0.794, Standard error: 0.0411.

Part B

Suppose Siri (an Apple digital assistant) is known to answer general facts correctly approximately 26.26% of the time. If a consumer asked Siri 105 questions about general facts, what is the probability that between 26.91% and 33.05% of them would be correct?

	1) 0.3829
	2) 1.5032
	3) 0.6171
	4) 11.8456
	5) -6.5223

Part C:

Fill in the blank. In a drive thru performance study, the average service time for McDonald's is 200.48 seconds with a standard deviation of 9.54 seconds. A random sample of 80 times is taken. There is a 10% chance that the average drive-thru service time is greater than ________ seconds.

	1) 188.25
	2) There is not enough information to determine this.
	3) 212.71
	4) 201.85
	5) 199.11

Part D:

A survey conducted by General Motors of 34 drivers in America, 30 indicated that they would prefer a car with a sunroof over one without. When estimating the proportion of all Americans who would prefer a car with a sunroof over one without with 90% confidence, what is the margin of error?

	1) 0.0050
	2) 0.0707
	3) 0.0553
	4) 0.0155
	5) 0.0906

Answer 1

a) *: 20 n-97 PEX: 0.2062 Standard erworben 0-2062.697231) 97 0.0011 opron u is correct. B) P=0.8626 0=105 0.2626 G Mp = P = 0.2626 reen Jo 2626 (0.7370) - 0.0u3 P(0.26916 2 28.3305) ,0 3305-0-2626 22 0.003 0:04 : P(0:15 2221.58) {p-value hom 2-table] P1221.58) - P(260.15) : 0.9429 -0.5596 : 0.38.33 0.3829 P10.2691-0.2626 0.043 c) P(x >x) = 0.1 plxcx): 0.9 PEXE) 1-2 I from a table oia corresponds I to 2:1-282] 2:1.282 - .12 1.282 => - 200.4% 9.54580 x = 20).85 u) 201-85 D) X30 na 34 Pž zů = 0.8923 909. ce , 8:04, 20111645 f= 24 sent 1.6455.8823(0-17%) In 34 0.0906 5) 0.0906