Stats - Statistics Flashcards by Hayley Mueller

What are the 4 types of data?

Nominal, ordinal, interval and ratio (NOIR)

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What 2 types of data - when the person is given a score or numerical value?

Interval or ratio data

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What 2 types of data - when the person is assigned to a category or tallied up as one point in a given category? (voting democrat or republican?)

Nominal or ordinal data

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If there’s only two categories with nominal data what’s it called? (gender - female or male)

Dichotomous

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What is interval or ratio data frequently called?

Continuous

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What’s data involves tallying people and involves putting people into non-ordered categories(e.g., gender or ethnicity), which can then be converted into a percentage?

Nominal data

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What data involves tallying people to see which ordered category each person falls into or we measure them on likert scales? (e.g., first born, second born, third born? or freshmen, sophomore, junior?)

Ordinal data

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What data involves obtaining numerical scores where the score values have equal intervals? - there is no zero (IQ test) or there’s no absolute zero (temperature)

Interval data

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What data involves taking numerical scores for each person where the score values have equal intervals and an absolute zero (income, number of children, score on an exam)

Ratio data

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What type of statistics describe what data (DV) are being collected?

Descriptive statistics

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What type of statistics has the goal of making inferences about the population from the sample?

Inferential

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When we are interested in measures of central tendency, variability and graphs are we looking at group data or individual scores relative to the whole group?

Group data

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What are the three measures of central tendency

Mean, median and mode

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What is the mean and how is it calculated?

the arithmetic average of a group of data
it’s calculated by adding up all the scores in the group & dividing it by the total number of scores

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What is the median?

the number that corresponds to the 50th percentile - where half the people are above the median and half the people are below it (MiDdle = MeDian)

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What’s the mode?

the most frequently occurring score (MOde = MOst)

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When data is skewed or there’s extreme scores do you use mode, median or mean?

Median is preferred

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What are the 3 elements of measures of variability

standard deviation, variance & range

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What is the measure of average deviation or spread from the mean in a given set of scores?

Standard deviation
E.g.,
- Set 1: 8, 10 & 12
- Set 2: 2, 10 & 18
- both have the same mean
- Set 2 has a larger standard deviation (spread)

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What the name of when the standard deviation squared?

Variance

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What’s the name of the difference between the highest score and the lowest score?

Range

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What type of data are graphed using a bar graph?

Nominal or ordinal

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The vertical line that goes up and down on a graph is called the

Y-axis

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The horizontal line that goes from right to left on a graph is called

X-axis

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Does the X or Y axis represent the categories (what two datas) or the scores (what two datas)

X-Axis categories: nominal or ordinal data scores: interval or ratio data

Does the X or Y axis represent the frequency

Y axis

How are percentile ranks depicted with the line on a graph?

flat or rectangular

What two datas are represented on a graph with curves?

Interval or ratio data

What type of skew has the mode as the lowest value and the mean has the highest value

Positive skew

What type of skew has the mean as the lowest value and the mode as the highest value

Negative skew

Which skew has the tail pointed to the left and which skew has tail pointed to the right

Positive = right tail end Negative = left tail end

On a positive skew, what has the highest value, median, mode or mean

mean

What the most detailed and most specific value that tells us exactly how someone did relative to a group?

Percentile ranks

Percentile ranks are considered ______ ________ scores

Norm reference scores (comparing you to the group)

What's the mean of z scores and what's the standard deviation

mean = 0 standard deviation = 1

What's the mean of t-scores and the standard deviation?

mean = 50 standard deviation = 10

What's the mean of IQ scores and the standard deviation

mean = 100 standard deviation = 15

What percentage of people will be in between +1 and -1

68%

What's the distribution of Ranks (Percentile Rank) within a bell curve in correlation to the z-scores

Z score = PR -3 = 0.1 -2 = 2.5 -1 = 16 0 = 50 1 = 84 2 = 97.5 3 = 99.9

What's the percentage of people between +2 and -2?

95%

What's the percentage of people between +3 and -3

99%

If equal amount of bonus points were given to someone in the 50th percentile rank as someone in the 97.5 percentile rank, which one will have a greater change in PR?

The person who was initially in the 50th percentile or mid range rank

What formula can help you find the z-score?

(raw score - mean) divided by the standard deviation

With population mean and the population standard deviation which one is sigma and which one is mu

Sigma = population standard deviation Mu = population mean

What are population values referred to as?

parameters

What are sample values referred to as?

Statistics

What does sampling error mean?

that our sample does not perfectly represent the population - it's a little off

How do we know there's a sampling error?

when taking a random sample of people like 25 people, the mean won't be exactly 100, while the population mean is 100

Formula for the standard error of the mean:

Sx= SDpop/square root of the sample size (N)

With the standard error of the mean formula, the standard error of the mean has what relation to the standard deviation of the population & what relation to the square root of the sample size

standard deviation of the population = direct relationship sample size = inverse relationship

To reduce the standard error of the mean, would you have to increase or decrease the standard deviation of the population and the sample size?

decrease the standard deviation increase the sample size

What's the most critical aspect of inferential statistics?

hypothesis testing

Are hypotheses expressed in terms of the sample or the population

Population, even though you test it using samples

What does the null hypothesis state regarding group differences

That there is no difference between groups

What is a researcher trying to do with the null hypothesis

Reject the null hypothesis meaning wanting to reject that there's no differences by concluding there are differences between groups

Where is the rejection region or the region of unlikely values on the bell curve?

within the tail-end of the curve

The alpha region refers to what

the size of the rejection region or region of unlikely region

Do you accept or reject the null hypothesis when it's in the rejection region?

Reject - which is what a researcher is hoping for

What kind of error is it called when we reject the null but later on, it turns out to be a mistake

Type 1 Error (reject = 1 C = type 1)

If your alpha score is 0.05 or 0.01 how likely is it to have made a type 1 error?

0.05 = 5% chance 0.01 = 1% chance

What kind of error happens when you accept the null when in fact there is significance

Type 2 error (accept = 2 C's = type 2)

If you correctly reject the null when significance is found

Power = we are all after power and power is what we want

Does power and alpha have an indirect or a direct relationship?

Direct: as power increases so does alpha

Does power and beta have an indirect or direct relationship?

indirect

When the null is accepted and this decision is correct what's it called?

It has no name