CHAPTER 2: NORMS AND BASIC TESTING

Question 1

Why do we need statistics?

Answer 1

We need statistics because a scientific study requires systematic observations and to extent that those observations are not by chance alone.

Question 2

What are the two purposes of statistical method? Define each.

Answer 2

1. The purpose is to make a description or the summary to evaluate some observation.
2. To make inferences, those are logical deductions of events that are not directly observed.

Question 3

Who used exploratory and confirmatory data analysis? What is the use of it?

Answer 3

John Turkey

A method used to form a systematic observation

Question 4

What is exploratory and confirmatory analysis?

Answer 4

Exploratory analysis is used for gathering data and display cues, while the confirmatory analysis is used to evaluate cues through a rigid statistical rules.

Question 5

What are the two methods used to make a systematic observation and numerical statements?

Answer 5

Descriptive statistics - to make a concise description of a collection of quantitative information.
Inferential statistics -to make inferences from a sample to larger group.

Question 6

What is measurement?

What is the use of measurement?

Answer 6

Measurement is the application of rules for assigning numbers to object.
It used to transform qualities of attributes into numbers.

Question 7

What are the three properties of scale of measurement? Define each

Answer 7

Magnitude - It is the moreness, it compares the two variables
Equal Intervals - The interval is equal in the different two pairs of points in the scale
Absolute 0 - nothing is exist

Question 8

What is magnitude, equal interval and absolute 0?

Answer 8

Magnitude - It “moreness”, an ordered relationship, you will the magnitude if we compare one to another.
Example. Height and weight, number of wins and loses
Equal interval - the difference of the numbers or points is the same with the difference of a different two points in a scale example. 4 minus 2 inches is 2 same as 10 minus 8 inches.
Absolute zero - obtained when nothing of the property is being measured exists.
Example: Measuring shyness using a scale

Question 9

4 types of scale

Answer 9

1. Nominal
2. Ordinal
3. Interval
4. Ratio

Question 10

What is the difference of nomimal to ordinal in terms of magnitude, equal intervals, and absolute 0?

What is the difference of interval to ratio in terms of magnitude, equal intervals, and absolute 0?

What is the example of interval and ratio?

Answer 10

Nominal has no properties of scale of measurement
Ordinal has magnitude, but no equal interval and absolute zero

Interval has magnitude and equal intervals, but no absolute zero
Ratio has all the three properties of scale of measurement

The example of interval - temperatures in degree of fahrenheit and Celsciu scale of temperature.

The example of ratio - It is also fahrenheit and celscius but exclude the o point. Another also is speed of travel and yards.

Question 11

What is frequency distribution?
How do use it?
What is the purpose of frequency distribution?

Answer 11

Also known as frequency polygon. It shows how frequent the score can be obtained or fall in a normal distribution.
It is used to summarize categorical variables.
The purpose is to visualize or illustrate the data collected in a sample.
It determines number of people obtained the scores within a distribution.

Question 12

What is percentile?
What is percentile rank?
What is the formula of percentile rank?
What is the use of percentile rank?

Answer 12

Percentile is a particular score that falls in a particular value within a frequency distribution or raw score units.
Percentile rank is the percentage of the examinee in the norm group that is below the score of interest.
Percentile equals b (no. below interest variable) over n (total number of the variables or population) times one hundred. (p = b/n x 100)
It is used to know the rank of a certain number in the population. It clarifys the interpretation of scores on a standardized test.

Question 13

What requires in the calculation of the percentile rank?

Why level of measurement is important? What measurement are permissible and which are not?

Answer 13

It requires that you know the total number of the population

It is important because we can tell what mathematical operation we will use for the measurement.

Nominal - not permissible
Ordinal - uses arithmetic, but hard to interpret
Interval - uses subtraction
Ration - all are permissible

Question 14

What is variable?
What is mean?
How to calculate mean?
Why do we use mean in statistics?

Answer 14

Variable - a score that can have different values
Mean - an average or sum of the variables.
Simply as x is equal to the sum of variable over n.
It is used to to get the standard deviation needed to get assess the variability of the set of a data.

Question 15

What is variance?
How to calculate population variance and sample variance?
How do we use variance?
Why do we use it?

Answer 15

Variance It is the difference between a score and a mean or a measurement of variability.
An average of the squared differences or deviation from the mean.

Population variance formula: summation of variable minus mean squared over n
Sample Variance formula: square root of the summation of variable minus mean squared over divided n minus one

It use to see kung gaano nagrerelate ang mga numbers sa bawat group of set.

Question 16

What is standard deviation?
What is the purpose of SD?
What is the formula?
How do you use it or advante of SD?
How Variance and Standard Deviation related?
What is the sum of the deviation around the mean?

Answer 16

Standard deviation is squared root of variance.
To know how far or close a set of group from the mean. Kapag mas malayo ang difference mas higher ang deviation, kapag mas malapit naman mas lower ang deviation.

SD is equal to square root of the summation of squared variable minus summation of variable squared divided by n over n minus 1

It is used to make a precise statement abot the distribution.

They are related because they both determined by mean of a group of numbers in a question.

It’s always zero

Question 17

What is Z Score?
How to calculate it?
What is the standard deviation of z score?
When and why do we use Z score?
What is the purpose of Z score?
How Z score and Standard deviation differed?
What do you mean by zero, positive and negative z-scores?
What is the mean of z-scores?

Answer 17

Z Score is the deviation of a score (x) and a mean in a standard deviation unit. Ang relationship ng values sa mean.

Formula: It is computed by z equals one variable minus mean divided by standard deviation. (z = x-x/SD)

SD: 1

Used and purpose: Z score is used because mean and standard deviation do not convey enough information about the assessment or accurate interpretation of data. It is more accurate than the two.

Difference: Standard deviation measures the variability of the group of sets. In terms of z scores, it measure the difference of score from the mean in terms of SD.

Zero indicates that the score is the same with the mean, positive z scores are above the mean score and negative is below the mean score.

The mean of z score is always zero.

Question 18

What is standard normal distribution?

Answer 18

Also known as symmetrical binomial probability distribution or bell curve.
It shows how events are frequently occurred within the range of the z scores.

Question 19

How do you use z score table to get the percentile rank?
Why do you add .5 in the score?
Why do you subtract .5 in the score?
How do you find percentile rank using the z scores?
Where can I use z scores?

Answer 19

Go to the left side to take the z score value and to the upper right side for the second decimal. Then , get the value of the z score.

You are going to add because it is a positive z score which means it is above the mean score.
Example 1. 10 (.5 plus .3643 equals .8643 or 86.43)
You are going to subtract because it is a negative z score which means it is below the mean score.
Example: -.75 (.5 - .2734 equals .2266 or 22.66)

Look in the table the closest value in the z score table.

It can be used to know your score performance in the test.

Question 20

What is T Score?
Who made T score?
How to calculate it?
What is the Standard deviation of T score?
When and why do we use T score?
What is the purpose of T score?
How T score and Z score differed?

Answer 20

A sample of standardized scores that which SD is 10 and mean is 50. It transform to standardized but not normalized.

Founder: W.A McCall on 1939
Formula: T is equal to 10 multiply to z scores + 50
Purpose: It is used to transform raw scores into more intuitive meaning.

SD: 10

Used: It is intended to use a one set of score that can be applied without standarizing all the set of numbers.

Difference: Z core has 0 in the mean distribution, while T score mean is set to 50.

Question 21

What are the three ways to present the results of the test?

Answer 21

Quartile, Decile and Stanines System

Question 22

What is quartile system?

Answer 22

Quartile is divided into 4 groups which has 25% intervals
Q1 - 25th 1/4
Q2 - 50th 1/2
Q3 - 75th 3/4
Q4 - 100th  1 whole

Question 23

Whgat is interquartile deviation?

Answer 23

The score that betweens 50 - 75

Question 24

What is Decile system?

Answer 24

It is divided into 10 groups.

It has 10% intervals

Question 25

What is stanine?

Answer 25

It is a standard nine which has 1 interval
SD - 2
mean - 5

Question 26

How to convert percentile to stanine?

Answer 26

Know the mean of the raw score and standard devation of the raw score.
Change raw scores to z scores and z scores to make it a percentile.
See the table of the z scores to make it to percentile and see the equivalent stanine.

Question 27

What are the four ways to describe the distribution?

Answer 27

Mean, Standard Deviation, Z scores and T Test