ch 3/4 Flashcards

1
Q

what are the steps in creating a frequency distribution table

A
  1. identify smallest and largest numbers, place the data in groups, count the number of observations in each group to find frequencies
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2
Q

what do histograms represent (x and y)

A

data and frequency

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3
Q

how do you find the relative frequency of a number

A

divide its frequency by the total number of observations

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4
Q

if putting numbers into a stem and leaf display, what would that look like (steps)

A

separate each number into stem (leading digit(s)) and leaf (SINGLE trailing digit)

put all the diff stems into a vertical column, and on the other side write the corresponding leafs

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5
Q

what characteristics describe a distribution curve for quantitative data

A

shape (unimodal, symmetric, outliers), centre, spread

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6
Q

how do you calculate mean

A

sum all the numbers up and then divide by the number of observations

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7
Q

how do you calculate median

A

either take the middle observation, or take the middle 2 observations and divide by 2

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8
Q

how do you calculate range

A

max. value- min. value

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9
Q

suspected outliers fall above or below

A

either Q1 -1.5x IQR or
Q3 + 1.5 x IQR

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10
Q

if distribution is roughly semetric.. use what as centre/spread measures

A

mean, variance, SD

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11
Q

if distribution is skewed, use what as centre/spread measures

A

median, IQR

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12
Q

what is the IQR

A

the range that falls in the middle 50% of observations

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