HI, Please I just want you to check these questions that these are correct or wr
ID: 3063956 • Letter: H
Question
HI, Please I just want you to check these questions that these are correct or wrong.. Also I want explaination of these questions, How answers came.. (5-8-10-13-16-17-18-19-20-21-22-23-24)
5- Given the set of scores {98, 97, 94, 94, 90, 89, 89, 86, 84, 78}, which score falls at the 80th percentile rank (PR) using the formula PR = B / N * 100?
97
94
90
89
6- Which type of graph should be used to plot hair color of the students in this class?
a. Bar Chart
b. Histogram
c. Scatterplot
All of the above can correctly be used.
7- Looking at the grouped frequency table on slide 6 of the Descriptive Statistics PowerPoint, what percentage of scores fall at or below the class interval of 66-70?
a.5% b.10% c.15% e.20%
8- Scores on this test should be graphed using which type of graph below?
Bar Chart
Histogram
Line Graph
Scatterplot
9- Which statistic(s) below represents the "average spread of scores around the mean"?
Standard Deviation
Variance
Both a and b are correct.
Neither a nor b is correct.
10- Because most of you will do better than average on this test, the distribution will most likely be...
bimodal.
negatively skewed.
normal.
positively skewed.
11- For both females and males, there are many younger than older students in college, thus the distribution is...
a. bimodal.
b. negatively skewed.
c. normal.
d. positively skewed.
12- Because skewed distributions tend to have peaks higher than a normal curve, they also tend to be __________.
Leptokurtic b. mesokurtic c. platykurtic d. None of the above.
13- What would be the most appropriate measure of central tendency for the distributions in the two previous items?
Mean b. Median c. Mode d. Range
14- What is the Mean for the following set of scores? {20, 20, 20, 30, 30, 40, 40, 50, 50, 50}
a. 25 b.30 c.35 d.40
15- What is the Median for the set of scores in the previous item?
a.25 b.30 c.35 d.40
16- What is the mode for the set of numbers in T2Q14?
a.30 b.40 c. Both a and b are correct. d. Neither a nor b is correct.
17- Using N-1, what is the variance for the following set of numbers? {2, 4, 6, 8, 15}
a.5 b.10 c.20 d.25
18- If you change the score of 15 in the previous item to a -5, what is the standard deviation for that set of scores (again using N-1)?
a.5 b.10 c.20 d.25
19- Using the same data set {2, 4, 6, 8, -5} what is the Z-score for the score of 8?
a.0 b.1 c.2 d.3
20- Given a raw score SD=85 and Mean=87.5, what would be the T-score for a raw score of 85? {hint - calculate the z-score first}
a.45 b.50 c.55 d.60
21- What would be the Stanine score for the person in the previous item?
a.4 b.5 c.6 d.7
22- Given an IQ SD = 15 and mean = 100, what percentage of people in the population have an IQ between 85 and 115?
a.34% b.68% c.95% d.99%
23- What percentage of people score above the Mean given a Standard Normal Distribution?
a.34% b.50% c.68% d.75%
24- What percentage of people score between 30 and 70 in the T-score distribution?
a.34%
b.68%
c.95%
d.99%
25- A Standard Normal Distribution has a Mean=_____ and a SD= _____.
a.0, 0
b.0, 1
c.1, 0
d.1, 1
Explanation / Answer
Note: Some questions are dependent on some slides that are not given. Therefore, other questions will be answered.
5- Given the set of scores {98, 97, 94, 94, 90, 89, 89, 86, 84, 78}, which score falls at the 80th percentile rank (PR) using the formula PR = B / N * 100?
97
94
90
89
Firstly the number of scores N = 10.
Given PR = 80
Using the formula PR = B/N * 100
=> 80 = B/10 * 100
=> 80 = 10B
=> B = 80/10
=> B = 8.
Thus the 80th percentile is the 8th rank score.
The 10th (least) rank score is 78 while the 9th and 8th rank scores are both 89.
Therefore, the answer is 89.
6- Which type of graph should be used to plot hair color of the students in this class?
a. Bar Chart
b. Histogram
c. Scatterplot
d. All of the above can correctly be used.
The color of hair has no value. So a bar chart needs to be used. In bar charts, we can have labels such as color which are not quantitative unlike histogram or scatterplot.
9- Which statistic(s) below represents the "average spread of scores around the mean"?
Standard Deviation
Variance
Both a and b are correct.
Neither a nor b is correct.
Both variance and standard deviation are measures of dispersion around the mean. However only variance gives average spread.
12- Because skewed distributions tend to have peaks higher than a normal curve, they also tend to be __________.
Leptokurtic b. mesokurtic c. platykurtic d. None of the above.
Leprokurtic have higher peak and therefore, higher kurtosis.
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