2011Fal
Quiz #1--Key
Date: 10/25/2011
A. MULTIPLE CHOICE QUESTIONS (50%)
1. Temperature is an example of a variable that uses a. the ratio scale b. the interval scale c. the ordinal scale d. either the ratio or the ordinal scale 2. The nominal scale of measurement has the properties of the a. ordinal scale b. only interval scale c. ratio scale d. None of these alternatives is correct.
3. Statistical studies in which researchers control variables of interest are a. experimental studies b. control observational studies c. non-experimental studies d. observational studies 3.
4. A statistics professor asked students in a class their ages. On the basis of this information, the professor …show more content…
Qualitative data can be graphically represented by using a(n) a. histogram b. frequency polygon c. ogive d. bar graph 6. Since the population size is always larger than the sample size, then the sample statistic a. can never be larger than the population parameter b. can never be equal to the population parameter c. can be smaller, larger, or equal to the population parameter d. can never be smaller than the population parameter 7. The value which has half of the observations above it and half the observations below it is called the a. range b. median c. mean d. mode 8. When data are positively skewed, the mean will usually be a. greater than the median b. smaller than the median c. equal to the median d. positive 9. The numerical value of the standard deviation can never be a. larger than the variance b. zero c. negative d. smaller than the variance 10. The value of the sum of the deviations from the mean, i.e., must always be a. less than the zero b. negative c. either positive or negative depending on whether the mean is negative or positive d. zero 11. If the coefficient of variation is 40% and the mean is 70, then the variance is a. …show more content…
What is the probability that a randomly selected resident is in favor of building the bridge?
f. What is the probability that a randomly selected resident is a man or in favor of building the bridge?
g. A randomly selected resident turns out to be male. Compute the probability that he is in favor of building the bridge.
3. (4%) What is the probability of drawing the 4 aces as the first 4 cards if 4 cards are drawn at random and without replacement from a deck of 52 playing cards? Please note that you are required to use conditional probability instead of counting rule. 4. (8%) In a large university, 20% of the students are business majors. A random sample of 100 students is selected, and their majors are recorded.
a. Compute the standard error of the proportion. b. What is the probability that the sample contains at least 12 business majors? c. What is the probability that the sample contains less than 15 business majors?
d. What is the probability that the sample contains between 12 and 14 business majors? 5. (6%) A random sample of ten examination papers in a course that was given on a pass or fail basis showed the following scores.
Paper Number Grade Status 1 65 Pass 2 87 Pass 3 92 Pass 4 35