A drug company wanted to test a new arthritis medication. The researchers found 700 adults aged 25-35 and randomly assigned them to two groups. The first group received the new drug, while the second received a placebo.
After one month of treatment, the percentage of each group whose arthritis symptoms decreased was recorded and compared. How many levels does the treatment in this experiment have?
A) 1 (months of treatment) B) 700 (number of respondents)
C) 10 (age span of respondents) D) 2 (medication or placebo)
Q. 2A researcher is interested in estimating the proportion of voters who favor a tax on e-commerce. Based on a sample of 250 people, she obtains the following 99 confidence interval for the population proportion p:
0.113 < p < 0.
171
Which of the statements below is a valid interpretation of this confidence interval?
A) If many different samples of size 250 were selected and, based on each sample, a confidence interval were constructed, 99 of the time the true value of p would lie between 0.113 and 0.171
B) If 100 different samples of size 250 were selected and, based on each sample, a confidence interval were constructed, exactly 99 of these confidence intervals would contain the true value of p.
C) If many different samples of size 250 were selected and, based on each sample, a confidence interval were constructed, in the long run 99 of the confidence intervals would contain the true value of p.
D) There is a 99 chance that the true value of p lies between 0.113 and 0.171
Q. 3z = -2 and z = -0.7
A) 0.0228 B) 0.758 C) 0.2192 D) 0.242
Q. 4Find the z-score for which the area under the standard normal curve to its left is 0.96
A) 1.03 B) 1.75 C) 1.82 D) -1.38
Q. 5A drug company wanted to test a new indigestion medication. The researchers found 400 adults aged 25-35 and randomly assigned them to two groups. The first group received the new drug, while the second received a placebo.
After one month of treatment, the percentage of each group whose indigestion symptoms decreased was recorded and compared. What is the treatment in this experiment?
A) the 400 adults aged 25-35
B) the one month treatment time
C) the percentage who had decreased indigestion symptoms
D) the drug
Q. 6A random sampling of sixty pitchers from the National League and fifty-two pitchers from the American League showed that 11 National and 13 American League pitchers had E.R.A's below 3.5.
A) z = -51.583 B) z = -0.857 C) z = -1.114 D) z = -4.320
Q. 7The area under the standard normal curve between 1 and 2 is equal to 0.1359. Scores on a particular aptitude test are normally distributed with a mean of 100 and a standard deviation of 10. Which of the following are equal to 13.59?
a.
The percentage of scores between 120 and 130
b. The percentage of scores between 110 and 120
c. The percentage of scores between 80 and 90
d. The percentage of scores between 90 and 120
e. The percentage of scores between 90 and 110
A) a, b B) b C) b, c D) e
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