Adding probabilities when you should multiply

"The AND/OR Mixup"

Probability & Statistics
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Assuming correlation means causation

"The Causation Confusion"

Probability & Statistics
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Finding median without ordering data first

"The Middle Muddle"

Probability & Statistics
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Giving probability greater than 1

"The Impossible Probability"

Probability & Statistics
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Plotting cumulative frequency at class midpoints

"The Midpoint Mistake"

Probability & Statistics
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Using frequency for the height instead of frequency density H

"The Height Mistake"

Probability & Statistics
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Averaging the values column instead of using frequencies

"The Frequency Forgetter"

Probability & Statistics
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Not changing fractions for without replacement

"The Replacement Forget"

Probability & Statistics
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Reading quartiles at wrong cumulative frequency values

"The Quartile Confusion"

Probability & Statistics
→

Reading the height instead of calculating the area H

"The Reading Error"

Probability & Statistics
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Treating extrapolation as reliable

"The Extrapolation Overreach"

Probability & Statistics
→

Using wrong total for denominator

"The Total Trouble"

Probability & Statistics
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Calculating the wrong class width H

"The Width Blunder"

Probability & Statistics
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Comparing box plots without using values

"The Vague Comparison"

Probability & Statistics
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Drawing line of best fit through all points

"The Connect-the-Dots Error"

Probability & Statistics
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Subtracting the wrong value for complementary events

"The Complement Confusion"

Probability & Statistics
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Tree diagram branches not summing to 1

"The Branch Blunder"

Probability & Statistics
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Using class boundaries instead of midpoints

"The Boundary Blunder"

Probability & Statistics
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Adding highest and lowest instead of subtracting

"The Range Reversal"

Probability & Statistics
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Leaving gaps between histogram bars H

"The Gap Problem"

Probability & Statistics
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Mixing up percentage and decimal forms

"The Percentage Pickle"

Probability & Statistics
→

Confusing expected frequency with probability

"The Expected Error"

Probability & Statistics
→

Giving the position as the answer instead of the value

"The Position Problem"

Probability & Statistics
→

Assuming outcomes are equally likely when they are not

"The Fair Fallacy"

Probability & Statistics
→