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AP Stats Flashcards

1
Q

What is STATISTICS?

A

The study of variability

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2
Q

What is VARIABILITY?

A

Differences… How things differ.

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3
Q

What are two branches of AP Stats?

A

Inferential and Descriptive

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4
Q

What are DESCRIPTIVE STATS?

A

Described data that was collected using pictures or summaries like mean, median, and mode.

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5
Q

What are INFERENTIAL STATS?

A

Data used to say stuff about the big picture. I.e. Small samples tells a lot about the whole food.

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6
Q

Compare DESCRIPTIVE and INFERENTIAL STATS.

A

Descriptive explains the data you have.

Inferential uses the data to say something about an entire population.

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7
Q

What is DATA?

A

Any collected information. Generally each little measurement.

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8
Q

What is a POPULATION?

A

The group you are interested in. Sometimes big such as “teens in the US”, and sometimes small like “teens in the school”.

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9
Q

What is a SAMPLE?

A

A subset of a population, often used to make inferences about populations.

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10
Q

Compare POPULATION to SAMPLE.

A

Populations are generally large, while samples are subsets of these populations. Samples are made to make inferences about populations.

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11
Q

Compare DATA to STATISTICS.

A

Data is each bit of info collected from the subjects. They are INDIVIDUAL little things we collect. It is summarized by, for example, finding the mean of a group of data. If it is a sample, it is called a mean “statistic”, if we have data from each member of population, it is called a mean “parameter”.

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12
Q

Compare DATA to PARAMETERS.

A

Data is each bit of info collected from the subjects. They are INDIVIDUAL little things we collect. It is summarized by, for example, finding the mean of a group of data. If it is a sample, it is called a mean “statistic”, if we have data from each member of population, it is called a mean “parameter”.

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13
Q

What is a PARAMETER?

A

A numerical summary of a population. Such as a mean, median, or mode of a population.

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14
Q

What is a STATISTIC?

A

A numerical range of a sample. Such as a mean, median, or mode of a sample.

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15
Q

We are curious about the average wait time at a Dunkin Donuts drive through in your neighborhood. You randomly sample cars one afternoon and find that the average wait time is 3.2 minutes. What is the population parameter? What is the statistic? What is the parameter of interest? What is the Data?

A

Population Parameter: The true AG. wait time at that Dunkin Donuts, it’s a number we don’t have and will never know.
Statistic: “3.2 minutes”, or the AVG. of the data collected.
Parameter of Interest: The same thing as the population parameter. In this case it’s the true AVG. wait time of all cars.
Data: The data is the wait time of each individual car

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16
Q

Compare DATA-STATISTIC-PARAMETER using a categorical example.

A

Data is individual measures, for example, “taco, taco, pasta, burger, taco, burger”… Statistics and parameters are summaries. A statistic would be “ 42% of the sample preferred tacos” and a parameter would be “42% of population preferred tacos.”

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17
Q

Compare DATA-STATISTIC-PARAMETER using a quantitative example.

A

Data is individual measures, for example how long a person can hold their breath: “45 sec, 64 sec, 32 sec, 68 sec.” That is the raw data. Statistics and parameters are summaries like “the average breath holding time in the sample was 52.4 seconds” and a parameter would be “the average breath holding time in the population was 52.4 seconds.”

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18
Q

What is a CENSUS?

A

Like a sample of the entire population, you get info from every member of the population.

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19
Q

Does a census make sense?

A

A census is okay for small populations (like Mr. Nystrom’s students) but impossible if you want to survey “all U.S. teens”

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20
Q

What is the difference between a PARAMETER and a STATISTIC?

A

BOTH ARE A SINGLE NUMBER SUMMARIZING A LARGER GROUP OF NUMBERS… But pppp parameters come from pppp populations… sss statistics come from ssss statistics.

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21
Q

If I take a random sample of 20 hamburgers from Five Guys and count the number of pickles on a bunch of them… and one of them had 9 pickles, then the number 9 from that burger would called___?

A

A datum, or a data value.

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22
Q

If I take a random sample of 20 hamburgers from Five Guys and count the number of pickles on a bunch of them… and the average number of pickles was 9.5 is considered a___?

A

Statistic. (it is a summary of a sample)

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23
Q

f I take a random sample of 20 hamburgers from Five Guys and count the number of pickles on a bunch of them… and I do this because i want to know the true average number of pickles on a burger at Five Guys, the true average number of pickles is considered a ___?

A

Parameter, a one number summary of the population. The truth, AKA the parameter of interest

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24
Q

What is the difference between a SAMPLE and a CENSUS?

A

With a sample, you get info from a small part of the population. In a census you get info from the entire population. You can get a parameter from a census, but only a statistic from a sample.

25
Q

Use the following words in one sentence: population, parameter, census, sample, data, statistics, inference, parameter of interest.

A

I was curious about a population parameter, but a census was too costly so I decided to choose a sample, collect some data, calculate a statistic and use that statistic to make an inference about the parameter of interest.

26
Q

If you are tasting soup.. Then the flavor of each individual thing in the spoon is the ___, the entire spoon is a ___.. The flavor of all that stuff together is like the ___ and you use that to ___ about the flavor of the entire pot of soup, which would be the ___.

A

Flavor of each individual thing is the DATA.
The entire spoon is a SAMPLE.
Flavor of it all together is the STATISTIC.
All can be used to MAKE AN INFERENCE about the flavor of the entire pot of soup, which would be the PARAMETER.

27
Q

What are RANDOM VARIABLES?

A

If you randomly choose people from a list, then their hair color, height, weight, and any other data collected from them can be considered random variables.

28
Q

What is the difference between QUANTITATIVE and CATEGORICAL VARIABLES?

A

Quantitative variables are numerical measures, like height and IQ. Categorical are categories, like eye color and music preferance

29
Q

What is the difference between QUANTITATIVE and CATEGORICAL DATA?

A

The data is actual gathered measurements. So, if it is eye color, then the data would look like this “blue, green. brown, brown, blue, brown, etc.” The data from categorical variables are usually words, often it is simply “YES or NO”. If it was weight, then the data would be quantitative like “125, 155, 223, 178, etc.” The data from quantitative variables are numbers.

30
Q

What is the difference between DISCRETE and CONTINUOUS VARIABLES?

A

Discrete can be counted, like “numbers of cars sold” they are generally integers (you wouldn’t sell 9.3 cars), while continuous would be something like the weight of a mouse… 4.344 oz.

31
Q

What is a QUANTITATIVE VARIABLE?

A

Quantitative variables are numeric, for example: Height, age, number of cars sold, SAT score.

32
Q

What is a CATEGORICAL VARIABLE?

A

Qualitative variables are like categories: Blonde, Listens to hip hop, female, yes, no, etc….

33
Q

What to sometimes call a CATEGORICAL VARIABLES?

A

Qualitative

34
Q

What is QUANTITATIVE DATA?

A

Actual numbers gathered from each subject. 211 Pounds. 67 Beats Per Minute.

35
Q

What is CATEGORICAL DATA?

A

The actual individual category from a subject, like “blue” or “female” or “sophomore”.

36
Q

What is a RANDOM SAMPLE?

A

When you choose a sample by rolling dice, choosing names from a hat, or other REAL RANDOMLY generated samples. Humans can’t really do this well without the help of a calculator, cards, dice, or slips of paper.

37
Q

What is FREQUENCY?

A

How often something comes up.

38
Q

DATA or DATUM?

A

Datum is singular.. Like “hey dude, come see this datum i got from this rat!” Data is plural.. “hey look at all that data Edgar got from those chipmunks over there!”

39
Q

What is a FREQUENCY DISTRIBUTION?

A

A table, or a chart that shows how often certain values or categories occur in a data set.

40
Q

What is meant by RELATIVE FREQUENCY?

A

The PERCENT of time something comes up (Frequency/Total)

41
Q

How do you find RELATIVE FREQUENCY?

A

Just divide frequency over the TOTAL

42
Q

What is meant by CUMULATIVE FREQUENCY?

A

ADD up the frequencies as you go. Suppose you are selling 25 pieces of candy. You sell 10 the first hour, 5 the second, 3 the third, and 7 in the last hour. The cumulative frequency would be 10, 15, 18, 25.

43
Q

Make a guess as to what RELATIVE CUMULATIVE FREQUENCY is.

A

It is the ADDED up PERCENTAGES. An example is selling candy, 25 pieces sold overall… with 10 the first hour, 5 the second, 3 the third, and 7 in the fourth hour. We’d take the cumulative frequencies 10, 15, 18, and 25 and divide by the total giving cumulative percentages.. .40, .60, .64, and 1.00. Relative cumulative frequencies always end at 100 percent.

44
Q

What is the difference between a BAR CHART and a HISTOGRAM?

A

Bar charts are for categorical data (bars don’t touch) and histograms are for quantitative data (bars touch).

45
Q

What is the MEAN?

A

The old average we used to calculate. It is the balancing point of the histogram.

46
Q

What is the difference between a POPULATION MEAN and a SAMPLE MEAN?

A

Population mean is the mean of a population, it is a parameter. Sample mean is a mean of a sample, so it is a statistic. We use sample statistics to make inferences about population parameters.

47
Q

What symbols do we use for POPULATION MEAN and SAMPLE MEAN?

A

Mu for population mean (parameter), x-bar for sample mean (statistic)

48
Q

How can you How can you think about MEAN and MEDIAN to remember the difference when looking at a HISTOGRAM?

A

Mean is the balancing point of a histogram. Median splits the area of the histogram in half.

49
Q

What is the MEDIAN?

A

The middlest number, it splits area in half (always in the position (n+)/)

50
Q

What is the MODE?

A

The most common, or the peaks of a histogram. We often use mode with categorical data.

51
Q

When do we often use MODE?

A

With categorical variables. For example, to describe the average teenagers preference. We often speak of what “most” students choose, which is the mode. It also tells the number of bumps in a histogram for quantitative data (unimodal, bimodal, etc..)

52
Q

Why don’t we always use mean, we’ve been calculating it all our life?

A

It is not RESILIENT, it is impacted by skewness and outliers.

53
Q

When we say “the average teenager” are we talking about the mean, median, or mode?

A

It depends.. If we are talking height, it might be he mean. If we are talking about parental income, it’ll most likely be the median. And if we were talking music preference, we’d probably use the mode to talk the average teenager.

54
Q

What is a clear example of where the MEAN would change but MEDIAN wouldn’t?

A

(This would show it’s resilience) Imagine if we asked eight people how much money they had in their wallet. We found that they had [1,2,2,5,5,8,8,9]. The mean of this set is 5, but so is the median. Now if someone had an outlying number of 9000 dollars, the median would remain 5, while the mean goes over 1000. 5 is a better description of the average person in a group that carries cash in their wallet.

55
Q

How are MEAN, MEDIAN, and MODE positioned in a skewed LEFT histogram?

A

It goes in that order from left to right. Mean-Median-Mode.

56
Q

How are MEAN, MEDIAN, and MODE positioned in a skewed RIGHT histogram?

A

It goes in the opposite order from right to left. Mode-Median-Mean

57
Q

Who chases the tail?

A

The mean chases the tail, and the outliers.

58
Q

Is there a way to study these cards efficiently?

A

Only if you read and rate honestly!!!

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