of a certain population are normally distributed with a mean of 1400 am Suppose
ID: 3222497 • Letter: O
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of a certain population are normally distributed with a mean of 1400 am Suppose the cranial capacities standard deviation of 125 om.The proportion ofthis population having aanial capacities more than 1275 am isapproximately (a) 084 (b) 0.16 (c) 0.34 (d) 0.68 2. Anonmal distribution has mean 15 and standard deviation 3.What interval includes about 99% of the probability? (a 12 to 18 (b) 6 to 24 (c) 9 to 2 (d 3 to 27 3 Samples are usually used in research because of (a size (b) cost (d all of the above 4. Adiettan has portioned people into age categoriesofunder 1&18-19, 50-69, and over 69. She is surveying 200 members from each oategory. This procedure is best described as (a random sampling (b) stratified sampling (c) convenience sampling (d systematic sampling 5 A sample off in cough syrup bottles is obtained by selecting every 100 botte on the fling machine's conveyor bet This is an example of a (a random sample (b) stratified sample (c) convenience sample (d systematic sample 6 A survey of pharmacists in the US regarding thesafety of citizens having their prescriptions fled pharmacists in other countries atalower cost wiliikely be (a) biased because it reflects the opinions in the US. of US oitizens (b) biased because reflects the opinions (c) unbiased because it reflectsthe opinions of pharmacists the US. (d) unbiased because it reflects the opinions of US citizens The following table displays the numbers of defective and nondefective medical devices produced by three plants working for the same manufacturer Plant A PlantB Plant C 180 190Explanation / Answer
1)
mean = 1400 , s = 125 , x = 1275
z = ( x -mean) / s
= ( 1275 - 1400 ) / 125
= -1
Now, we need to find p ( z>. -1)
p(x > 1275 ) = p ( z > -1) = 0.8413
2) Mean = 15 , s = 2
For 99% interval = mean - 3s , mean +3s
mean - 3s = 15 - 3 * 2 = 9
mean +3s = 15 + 3 * 2 = 21
Option c)
3)
All of the above
4) Stratified sampling
Stratified sampling refers to a type of sampling method . With stratified sampling, the researcher divides the population into separate groups, called strata. Then, a probability sample (often a simple random sample ) is drawn from each group.
5)
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