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# cumulative frequency upper bound watch

1. why is the upper bound of 70<(or equal to) x < 100 70?
i thought it would be 100.

for other cumulative frequencies i have done it has always been this? so why is this different

this is from question 6v)
http://mei.org.uk/files/papers/s108ja_leqa.pdf
2. (Original post by esmeralda123)
why is the upper bound of 70<(or equal to) x < 100 70?
i thought it would be 100.
It is 100.

In the table the 70 is in parentheses, it's an extra class that's been added in prior to the class, to give you the zero cumulative frequency.
3. (Original post by ghostwalker)
It is 100.

In the table the 70 is in parentheses, it's an extra class that's been added in prior to the class, to give you the zero cumulative frequency.
ok thank you
for the next question it asks to find the 90th percentile
i know that they need to find the 43.2 -> 43rd value but how did they get 166 from the grouped data?
what formula or method did they use to find it, i know that it lies in the category 150-170 because the frequency there is 45

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