# Statistics christmas 10

what is the difference between histograms and bar charts? (4)
(1) there are no spaces between the bars on histograms (2) class intervals are not equal (3) y axis is labeled frequency density, not just frequency (4) it is the area of the bar that matters, not the height
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how do you answer a histogram question? (2)
(A) count the squares (B) calculate the area using frequency density = class width x density
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what are the types of data? (6)
primary (collected by you) secondary (taken from others) qualitative( words) quantitative (numbers) - discrete (can only be certain numbers) continuous ( could be any number)
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what must you always remember? (5)
title, labels, key, penil, ruler
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name the ways to display data? (9)
bar charts (bar charts, dual bar charts, composite bar charts) histograms, frequency polygons, vertical line graph, pictograms, stem and leaf, pie charts
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what are the types of sampling? (4)
random, stratified - cluster, quota and systematic
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what is random sampling
where there is no pattern or thought put into who is selected.everyone has an equel chance of being selected
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what is stratified sampling
the population is properly represented this is done by the sample size population size x stratum size
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describe cluster, quota and systematic sampling
cluster = where the population naturally splits into groups eg towns // quota sampling = when the population is selected due to certain characteristics eg age // systematic = when a random starting point then people are chosen at regular intervals
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describe symetrical, negatively skewed and positively skewed box plots
symmetrical = median is in the middle of the box plot // negatively skewed = median is closer to the upper quartile // positively skewed = median is closer to the lower quartile
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what must you avoid when designing a question? (4)
(1)over lapping groups (2) being biased / leading (3) may be too personal (4) being too vague - include figures!
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how do you find the mean of a frequency table?
the total of fx over the total of the frequency
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## Other cards in this set

### Card 2

#### Front

how do you answer a histogram question? (2)

#### Back

(A) count the squares (B) calculate the area using frequency density = class width x density

### Card 3

#### Front

what are the types of data? (6)

### Card 4

#### Front

what must you always remember? (5)

### Card 5

#### Front

name the ways to display data? (9)