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quiz 10 70

Question 7   Your answer is CORRECT . Mars Inc. claims that they produce M&Ms with the following distributions : Brown 30 % Red 20 % Yellow 20 % Orange 10 % Green 10 % Blue 10 % How many M&Ms must be sampled to construct the 90 % confidence interval for the proportion of yellow M&Ms in that bag if we want a margin of error of ± .15 ?
a ) 23
b ) 20
c ) 19
d ) 11
e) 12
f) None of the above
Question 8   Your answer is CORRECT . An experimenter flips a coin 100 times and gets 51 heads . Find the 85 % confidence interval for the probability of flipping a head with this coin .
Question 9   Your answer is CORRECT . Suppose that prior to conducting a coin - flipping experiment , we suspect that the coin is fair . How many times would we have to flip the coin in order to obtain a 96.5 % confidence interval of width of at most . 17 for the probability of flipping a head ?
Question 10   Your answer is CORRECT . It has been observed that some persons who suffer acute heartburn are diagnosed with it again within one year of the first episode . This is due , in part , to damage from the first episode . In order to examine the percentage of the persons who suffer acute heartburn a second time , a random sample of 1100 people who suffered acute heartburn was collected . It was observed that 17 of them again suffered acute heartburn within one year . Select a 99 % confidence interval for the true proportion of those who suffer a second episode .
Question 11   Your answer is CORRECT . When solving for the sample size required to estimate p to within a particular margin of error , under what circumstances do we use p ! = .5 ?
a) When p ! = . 4 and 1 - p ! = . 6
b) When the variance is equal to . 5 or when we desire a most conservative sample size .
c) When the computed value of p ! = . 5
d) When we have no prior information on the approximate value of p ! or p .
e) When the margin of error desired is less than or equal to . 5
f) None of the above
Question 12   Your answer is INCORRECT . Television viewers often express doubts about the validity of certain commercials . In an attempt to answer their critics , a large advertiser wants to estimate the true proportion of consumers who believe what is shown in commercials . Preliminary studies indicate that about 40 % of those surveyed believe what is shown in commercials . What is the minimum number of consumers that should be sampled by the advertiser to be 85 % confident that their estimate will fall within 1 % of the true population proportion ?