Midterm 1: chapter 1, 2, 3 Flashcards
which distribution is the most homogeneous given the following: (1) mean = 100 and variance = 25; (2) mean = 120and variance = 36; (3) mean = 90 and variance = 49?
(1) mean = 100 and variance = 25
the level of measurement that, at best, can rank subjects is ______?
nominal
what is the appropriate procedure for weighting the score on the final examination to count twice as much as the midterm examination score?
Double the T score for the final and add this to the T score for the midterm.
What happens to the mean and the standard deviation of a set of score scores if each score is increased by 10?
The mean changes and the standard stays the same
Assume that a teacher wants to grade on the curve. The average grade will be a C. She will give 10% of the class an A and 10% an F. What is the T-score cutoff to pass the test (i.e., earn a grade of D or better)? Round to the nearest whole number. (Hint: Find the z score from the table of normal-curve areas.)
37
Reaction-time tests are what level of measurement?
ratio
On a knowledge test, a score of 10 is at the 40th percentile. What does this indicate?
40 percent of the test scores were at or below 10.
What percent of the cases would you find in a distribution between the median and P15?
25%
The standard deviation is an indication of ___?
the variability of a set of test scores around the mean
the most stable measurement of central tendency with interval data is the_____?
mean
the best reason for using T scores with three skill items on a basketball test is to ___?
add scores together
three of the following four things have something in common. Which one doesn’t belong.
Mean, Range, Standard Deviation, or Variance
mean
which of the following contain an absolute zero point?
ratio
you want to make the norms as easy as possible for students, parents, administrators, and teachers to understand. How would you report your results?
raw scores and percentiles
consider the following scores: 2,3,3,4. What is the standard deviation. Round the the nearest tenth.
7
Kelly’s T score was 60. what is her Z score?
1.0
which of the following tests will carry the greatest weight if you simply add the total number of correct items to obtain a total score for the course grade?
items = 200; mean = 120; standard deviation = 40
who did best relative to his or her classmates? that is, who had the highest percentile?
unable to determine from data given
the average number of points scored by NBA teams last year was 100 per game. the standard deviation was 30 points. Ninety-five percent of the games had NBA teams scoring fewer than how many points? Round to the closet whole number.
150
what percent of observations lies between -1.96 and +1.96 standard deviations?
95%
ranking scores on a test from highest to lowest facilitates finding which of the following measures?
median and mode
a pupil attains a raw score of 82 on a test with a mean of 100 and a standard deviation of 12. what is the corresponding T score?
35
scholastic aptitude test (SAT) scores are normally distributed with a mean of 500 and a standard deviation of 100. a student’s SAT score is 430. what is the student’s percentile? round to the nearest whole number.
24
the average athlete is able to begin activity 90 days after having a knee operation. the standard deviation is 20 days. sixty-eight percent of athletes are able to participate within how many days? round to the nearest day.
99
which of the following does not belong with the other two?
a. T score = 70
b. Z score = 2.0
c. percentile = 95
the Z score at the 70th percentile is ?
0.52
which pair of scores represents the same level of measurement?
distance and height
what is the simplest measure of variability to calculate?
range
what is the mean of a T score?
50
what percentage of the normal curve lies between -1.53 and +1.37 standard deviation units from the mean?
85.17
what is the T score associated with the 97.5th percentile?
70
which of the following does not represent a nominal scale of measurement?
height
How can a standard z score be changed to a T score?
multiply by 10 and add 50
Which of the following measurement scales is related to naming or classifying?
nominal
Distribution that has many more high scores than low scores is____?
negatively skewed
Distribution around a given mean and standard deviation that is mesokurtic with no skewness is said to be
normal
how many students out of 100 would be between the z score of .33 and .94?
20
put score limits on 95 percent of the scores when the 84th percentile is a score of 60 and the 16th percentile is a score of 50
45 to 50
with a mean of 27.1 and a standard deviation if 3.9, the T scores for the raw scores 26 and 32 are
47 and 63
mean = 196, standard deviation = 14, and N=17. What is the raw score for a z score of 0.35?
201
John scored at the 45th percentile on the course midterm. Which interpretation go his score is the best?
John had a better score than 45% of the people tested.
which of the following is not affected by the value of every score in the set on which it is calculated?
median
for a set of 5,000 scores, the mean is 98, the median is 110, and the mode is 120, which describes the distribution?
negatively skewed
for a 100 point test, the cutoff for an F is 60 points. With a mean of 74 and standard deviation of 10, how many students out of 100 would receive an F?
8
SAT scores are normally distributed with a mean of 500 and a standard deviation of 100. A students SAT score was at the 30th percentile. what was her raw score? round to the nearest whole number.
448
what score represents P16 if the mean of the distribution is 300 and the standard deviation is 10?
290
in a normal distribution, the mean divided by the median equals _____?
1
why are standard scores so important?
they permit scores to be compared more appropriately
you are discussing the heterogeneity of your tennis class results with one of your fellow teachers. which of the following terms will you probably use in the discussion?
standard deviation
the mean on a test was 50 and the standard deviation was 20. what percent of people scored between a Z score of .80 and raw score of 68?
2.78
the mean on a test was 200 and the standard deviation was 20 points. what percent of people scored less than 170? round to the nearest whole number.
7
given that the mean is 80 and the standard deviation is 10, which of the following does not belong?
P = 38.69
what area of the normal curve lies between a Z score of .48 and a T score 0f 42?
0.00
given the variance = 100 and P16 = 985, which of the following is probably the mean?
995
T score = 43. what is the percentile?
24.20