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# Calling Misc Mathematicians

a) A student travels by bus to get to school. On twenty-two separate occasions, she makes a note of the length of time she has to wait for the bus to arrive. The results are shown below in table Q9a:

Waiting time (mins)

time in Minutes:4 5 6 7 8 9

No. of times :2 4 7 6 2 1

Table Q9a

Calculate the mean and standard deviation of the waiting time.

I can do the mean, but wtf the standard deviation.

Waiting time (mins)

time in Minutes:4 5 6 7 8 9

No. of times :2 4 7 6 2 1

Table Q9a

Calculate the mean and standard deviation of the waiting time.

I can do the mean, but wtf the standard deviation.

Original Poster

lol @ homework, what am i 13?

im doing a past paper, and i have no idea what Standard Deviation is, I looked it up on Wikipeida, and still dont know, so I was hoping it someone would break it down.

kthnxbai

thisquestion is or what standard deviation is?Original Poster

yes the answer is 2.42, but I dont know you would get it.

the mean is 3.67

Just use the equation(s) here

Banned

]http//hu…dev

Original Poster

thanks just what i needed raped!

Original Poster

I dont work for Nasa:p

:giggle:

You say that you can work out the mean, and have 3.67. How can that be right for the average wait time when the time ranges from 4 to 9?

Original Poster

No. of times :2 4 7 6 2 1

is what you do the average by:thumbsup:

4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 9

a nice example similar to your question with a little applet to check your answers

but that doesnt give you the average waiting time

and sd = 1.27

i could never get to grips with this stuff, glad i left maths at the door at GCSE!

You are trying to find the average time waiting for the bus not the average of the number of no. of times?!

Look at my previos post.

Banned

Original Poster

CIA level

, i know how to do it know thanks to hotukdeals.com/ite…t=6

as well as others:thumbsup:

off topic but remember that bodybuilding website u linked in magicbeans gym workout thread the other day, i didnt realise u were a member was just goin thru and i saw ur name and though oh black gerbil lol

Banned

As you can't give me a straight answer, I am not inclined to offer any further advice. However, my guess is you are at GCSE level. If you are doing anything below the higher teir, don't worry about SD. If you are doing A Level or Higher teir GCSE - you have little hope.

Original Poster

haha you

tryingto get me mad bra:roll: