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S1 box plots

a. 50 % ?
b. 1/4 of the musicians... will that be the lower quartile? 54 kg?
c. it represents an outlier
d.symmetrical
e. i am really not sure how to continue? is the probability going to equal 0.25?

Original post by sadboynerd

a. 50 % ?

Agreed.

b. 1/4 of the musicians... will that be the lower quartile? 54 kg?

It's the upper quartile, and yes, it's 54 kg.

c. it represents an outlier

OK. And an instrument?

d.symmetrical

Look again. Whilst the middle 50% look symmetric, the remainder don't.
Edit: It seems others disagree with me on this one. If you have a specific test as Anonymous619 mentions, then go with that.

e. i am really not sure how to continue? is the probability going to equal 0.25?

Well 45 is the mean, so P(X<45) = 0.5

You want to look at the upper (or lower, but upper is easier) quartile

P(X<54) = 0.75

(edited 7 years ago)

Reply 2

Shaanv

date is symettrically skewed when the difference between the lower quartile and median is equal to the difference between the upper quartile and the median. So the skewness of the data is symettrical.

Reply 3

Anonymous619

Original post by sadboynerd

a. 50 % ?
b. 1/4 of the musicians... will that be the lower quartile? 54 kg?
c. it represents an outlier
d.symmetrical
e. i am really not sure how to continue? is the probability going to equal 0.25?

a) 50% as the 45kg is the median line
b) Charge made anything above Q3 = 54
c) represents an outlier - too extreme for the data - heavy instrument
d) symmetrical as Q3-Q2=Q2-Q1
e) 54-45/σ = 0.67 so σ = 13.43

This video may help you with e)
https://www.youtube.com/watch?v=Xzmp4nlcjYg

Reply 4

Shaanv

in regards to e, P(X<45)=0.5.
Then P(X<54)=0.75.
Consider the standard normal distribution where:
P(Z<{[54-45]/standard deviation})=0.75
Use your table on the standard normal distribution to solve for standard deviation.