Statistics

Question 1

Ordered Array

Answer 1

Data table organized in a way to serve a specific purpose. e.g. ordering test grades from highest to lowest

Question 2

Percentile

Answer 2

The value or score on an ordered array of data that indicates the percentage of the scores that fall at or below that value

Question 3

Quartile

Answer 3

Three specific percentiles: Q1 - 25%, Q2 - 50%, and Q3 - 75%

Question 4

Interquartile Range (IQR)

Answer 4

Difference between Q3 and Q1. Used to characterize the bulk of the population

Question 5

Frequency Distribution

Answer 5

Shows the repetition of the same result in a data set. A frequency distribution indicates how many students scored at the same level.

Question 6

Histogram

Answer 6

a graphic representation of related data. In simplest terms, a histogram is a connected bar graph of the data.

Question 7

Normal Curve

Answer 7

Standard distribution curve
mode = mean = median

Question 8

Negative Skew

Answer 8

Data that causes a longer tail on the left side. The mean is to the left of the peak.
Mean < Median < Mode

Data that favors the right side of a normal curve. The right side of the normal curve is increased.

Question 9

Positive Skew

Answer 9

Data that causes a longer tail on the right side. The mean is to the right of the peak.
Mean > Median > Mode

Data that favors the left side of the normal curve. Data that causes the left side of the normal curve to increase.

Question 10

Central Tendency

Answer 10

A single data value used to describe an entire data set. This answers the question, “How did the class do as a whole?”

Question 11

How is central tendency measured?

Answer 11

By the mean, median, or mode.

Question 12

Mode

Answer 12

The data value that occurs most often

Question 13

Which do the highest and lowest points in a data set affect more, Mean or Median

Answer 13

The value of highest and lowest scores affects the mean value but not the median value

Question 14

What is the formula for calculating the boundaries of a data set?

Answer 14

Lower boundary: Q1 - IQR
Upper boundary: Q3 + IQR

Used to determine outlier scores

Question 15

Box and Whisker Plot

Answer 15

A graphical way to determine how spread out the quartiles are

Question 16

Stem and Leaf Plot

Answer 16

Simple way to create a bar graph (histogram) using the first common number of a set of test scores (the stem) and ordering all the scores with that first common number behind it (the leaves)

e.g.
9|0,2,4 from 90, 92, 94
8|1,6,8 from 81,86,88
7|2,4,5,7,9 from 72,74,75,77,79
etc.

The longer the stem that holds the leaves, the more people who earned that grade.

Question 17

Variance or Variability

Answer 17

Describes how spread out the data is

Question 18

Value Added Assessment

Answer 18

A method of determining what you personally have added to the education of the students compared to other teachers of the same course

Question 19

Steps to calculating one standard deviation

Answer 19

Step 1: determine the mean

Step 2: Subtract the mean from each score

Step 3: Square the result of each answer from step 2

Step 4: Add the numbers from step 3 together

Step 5: divide the total from step 4 by the number of scores minus 1

Step 6: take the square root of step 5

Question 20

Percentages that correlate to results falling within one, two, and three standard deviations.

Answer 20

68% = 1 Standard deviation
95% = 2 Standard deviations
99.7% = 3 Standard deviations

Question 21

Pearson correlation coefficient scores of -1, 0, and 1

Answer 21

-1 = inversely related
1 = directly related
0 = unrelated

Question 22

Bimodal distribution

Answer 22

Two modes or peaks within the same distribution of data

Question 23

What is the best method for calculating central tendency when the variance is small

Answer 23

mean

Question 24

Relationship between Scale Score, the Standard Error of Measurement (SEM), +1 SEM, and -1 SEM

Answer 24

+1SEM = Scale score + SEM
-1SEM = Scale score - SEM
SEM = half the range between -1SEM and +1SEM

Question 25

A standard score is calculated by . . .

Answer 25

using the
1) raw score, (x)
2) the distance from the mean, (m)
3) the standard deviation of the distribution. (s)

standard score = (x - m)/s

Question 26

Disaggregated

Answer 26

separated into parts.

e.g. breaking data down by socioeconomic status

Question 27

Reliable test

Answer 27

Yields consistent results

Question 28

Valid test

Answer 28

Yields accurate results

Question 29

What is a Standard Error of Measurement (SEM)?

Answer 29

The difference between the actual score that a student achieves on an exam and her hypothetical score.

a measure of how much measured test scores are spread around a “true” score.

Question 30

What is a Standard Error of Measurement (SEM) useful for?

Answer 30

This measurement is used to determine the accuracy of a test in gauging student knowledge.