Measures of Central Tendency

(Mean, Median,Mode and Range)

Mean and how to work it

Mean- The average of a number (or equal shares) of different numbers or amounts. (Also in Notes)

How to work out mean- Add up all the numbers, then divide your total amount by how many numbers you have.

Example sentence- I walked my dogs everyday for the past weeks, i walked him 35 minutes Monday, 30 mins Tuesday, 32 mins Wedenday, 28 mins Thursday, 25 mins Friday, 38 mins Saturday, 34 mins Sunday. The total minutes walked that week was 222 mins. Then to get the answer divide by all the number pairs and you will get the average as 31.7.

Median and how to solve it

Median- The middle value or an ordered set of numbers. (Also in Notes)

How to work it- Order it from least to greatest, then cross out the numbers evenly intill you get the middle number. Also if the amount of numbers is even, then you have to add the two numbers in the middle, then divde the new number by how many numbers in the middle you had, this will get you your new average (middle number)

Odd median- 1,1,2,3,3,4,6,6,7,7,9, Even median-2,3,3,4,6,6,7,7,7,8, 6+6=12 divide by 2 = 6

Mode and how to get the answer

Mode- This is the number that accurs the most. (Also in Notes)

How to get the answer- look at all your numbers in a graph or T-chart (stem and leave plot), and find the numbers that apper the most often.

Example- You have 30,30,54,56,30,54,33,37 the number that occurs the most often is 30.

Range and how to solve it

Range- This is when you have the greatest and smallest number and subtract them. (Also in Notes)

How to solve it- If you have a list of numbers like this- 55,23,10,68,71,25 you find the smallest number and in this case it is 71 and 10. Then you subtract them both to get the range, which would be 71-10=59

STAAR questions for Mean, Median, Mode and range

Staar Mean- The weather in Texas for the week was 86F,85F,97F,99F,78F,101F,100F, what is the mean? Answer is-92

Staar Median- What is the Median of 2,3,4,7,7,8,9,10,11? Answer is- 7.5

Staar Mode- What is the Mode of these numbers? 31,30,30,29,28,31,39,31. Answer- 31

Staar Range- I walked my dog everyday, I walked 30,50,31,32,45,52 Minutes, what is the range of the time i walked my dog? Answer-22

Citations

Http://www.google.com/search?q=median+mean+pictures&hl=en&source=lnms&tbm=isch&sa=X&ei=n

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