Download 1. For a particular sample of 63 scores on a psychology exam, the

1. For a particular sample of 63 scores on a psychology exam, the following results were obtained.First
quartile = 47 Third quartile = 81 Standard deviation = 11 Range = 68 Mean = 70 Median = 71 Mode =
77 Midrange = 55
Answer each of the following:
I.
What score was earned by more students than any other score? Why?
II.
What was the highest score earned on the exam?
III. What was the lowest score earned on the exam?
IV.
According to Chebyshev's Theorem, how many students scored between 48 and 92?
V.
Assume that the distribution is normal. Based on the Empirical Rule, how many students scored
between 59 and 81?
2. Find the range, standard deviation, and variance for the following sample data:
77, 67, 5, 30, 19, 79, 9, 23, 1, 51, 56, 82, 27, 1, 9, 90
3. In terms of the mean and standard deviation:
-
What does it mean to say that a particular value of x has a standard score of +2.0?
-
What does it mean to say that a particular value of x has a z-score of -1.2?
4. A student scored 37 percent on a test, and was in the 23rd percentile. Explain these two numbers
5. In each of the four examples listed below, one of the given variables is independent (x) and one of the
given variables is dependent (y). Indicate in each case which variable is independent and which variable
is dependent.
I. Taxi fare; Length of ride
II. Gas consumption; Miles driven
III. Crop yield; Rainfall
IV. Monthly sales; Monthly commission
6. A sample of purchases at the local convenience store has resulted in the following sample data, where
x = the number of items purchased per customer and f = the number of customers.
·
What does the 11 stand for in the above table?
·
Find the midrange of items purchased.
·
How many items were purchased by the customers in this sample?
7. Scores on the Stanford-Binet Intelligence scale have a mean of 100 and a standard deviation of 16,
and are presumed to be normally distributed. A person who scores a 116 on this scale has what
percentile rank within the population? Show all work as to how this is obtained.
8. SAT I scores around the nation tend to have a mean scale score around 500, a standard deviation of
about 100 points and are approximately normally distributed. A person who scores 700 on the SAT I has
approximately what percentile rank within the population? Show all work as to how this is obtained.
9. Construct a scatterplot for the (x, y) values below, and answer the following questions. You needn’t
submit your scatterplot with your answer.
x
y
1
-1
2
-2
3
4
4
6
5
5
- Would the correlation between x and y be positive or negative?
- How would you interpret these data in terms of linear regression?
10. What does it mean for the trials to be independent in a binomial experiment?