1 . Of 250 adults who tried a new multi-grain cereal, “Wow!”, 187 rated it excellent; of 100 children sampled, 66 rated it excellent. What test statistic should we use?
Answer
z-statistic
Right one-tailed test
Left one-tailed test
Two-tailed test
2 . The weekly mean income of a group of executives is $1000 and the standard deviation of this group is $100. The distribution is normal. What percent of the executives have an income of $925 or less?
Answer
About 15%
About 85%
About 50%
About 23%
3. A random variable from an experiment where outcomes are normally distributed
Answer
can have any value between – ∞ and + ∞.
can have only a few discrete values.
can have a mean of 0 and a standard deviation of 1.
can have no values.
4) Which of the following is true in a normal distribution?
Answer
Mean equals the mode and the median
Mode equals the median
Mean divides the distribution into two equal parts
All of the above are correct