# Statistics - Mean

a - answer    s - solution    v - video    d - discussion

## Question 1

To calculate the mean, add up all the numbers, and divide by how many there are.
Find the mean of the following (non calculator):

a) $2,3,7$a s v d
b) $1,4,7,8$a s v d
c) $4,8,11,12,15$a s v d
d) $8,2,6,8$a s v d
e) $11,2,14,5$a s v d
f) $2,3,4,5,6$a s v d
g) $9,5,7,3,6,8,4$a s v d
h) $8,12,4,17,4$a s v d
i) $18,1,17,14,6,2$a s v d
j) $101,102,105,108$a s v d
k) $5,6$a s v d
l) $7,9,9,4$a s v d
m) $13,2,7,18,3$a s v d
n) $18,97,14,11$a s v d
o) $64,14,43,11,72$a s v d

## Question 2

Find the mean of the following (calculator):

a) $14,17,22,44$a s v d
b) $35,5,36,22,15$a s v d
c) $47,12,94,24,1,56$a s v d
d) $3,3,3,3,3,5,5,5,5,5$a s v d
e) $131,166,131,155,201,59$a s v d
f) $22.4,55.9,18.5,24.3$a s v d
g) $101.4,55.8,23.7,187.3,11.2,400$a s v d
h) $323.9,523.11,53.4,911.54,75.5,322.74,632.55,233.76$a s v d

i) $3146,414,5317,1432,8794,1342,5237,2381,1235,548,587,4892$a s v d

## Question 3

Answer the following worded questions:

a) I ate the following servings of fruit in a week:
$3,4,3,5,2,0,4$
What was the mean amount of fruit I ate each day?a s v d

b) Over a season I scored the following in matches:
$4,7,2,4,6,2,5,2$
What is my mean score?a s v d

c) What is the mean of the following prices?
$\$2.50,\$4.25,\$3.75,\$8,\$1.50$a s v d d) Sam has$10$friends at his birthday. Their ages are:$12,12,13,12,13,12,10,13,12,11$What is their mean age?a s v d e) The hourly wage of$5$workers at Arms Factory are: £$8,$£$10,$£$14,$£$11,$£$13$The hourly wage of$6$workers at Bran Factory are: £$7,$£$13,$£$14,$£$10,$£$9,$£$10$Which factory has a higher mean wage and by how much?a s v d ## Question 4 Find the missing piece of data in each of the following if their mean is$10$. a)$9,\square,11$a s v d b)$6,\square$a s v d c)$\square,16,2$a s v d d)$25,\square,3,8,20,1$a s v d e)$4,5,6,7,8,9,\square,$a s v d ## Question 5 Find the missing piece of data in each of the following if their mean is$12$. a)$12,\square,13$a s v d b)$0,\square$a s v d c)$15,16,13,\square,15$a s v d d)$13.5,\square,12.5,18.5,5.5,7.5$a s v d ## Question 6 Find the missing piece of data in each of the following if their mean is$6.6$. a)$\square,6.6$a s v d b)$\square,10,3$a s v d c)$0,8.4,\square,4.2,10$a s v d d)$6.75,\square,2.2,8.25,9.8,16,0.5$a s v d ## Question 7 Find the mean of the following data set: a) Result Frequency 9 1 10 3 11 1 12 5 a s v d b) Result Frequency 25 3 26 4 27 2 28 1 a s v d c) Result Frequency 4 8 5 4 6 10 7 1 8 2 a s v d ## Question 8 Find the mean of the following (involves negative numbers): a)$-4,-5,-9$a s v d b)$-16,-5,-20,-11$a s v d c)$-2,2$a s v d d)$-4,-2,3,11$a s v d e)$-10,0,15,-4,-6$a s v d f)$7,-7,8,-8,9,-9$a s v d g)$44,-6,8,-20,15,-35$a s v d h)$-72,84,22,-16,0,44,50,-204$a s v d i)$-125,215,-12,61,77,-821,521,22,124,-5,-124,13$a s v d j)$-5.2,7.3,-33,-3.6,-66,-12.7,22,5.94$a s v d ## Question 9 Find the missing piece of data in each of the following if their mean is$0$. a)$\square,6$a s v d b)$12,\square,-1$a s v d c)$\square,32,-16,8,-4.4$a s v d d)$-6,20,\square,44,-18,-9,0$a s v d ## Question 10 Find the missing piece of data in each of the following if their mean is$-5$. a)$\square,-2$a s v d b)$0,\square$a s v d c)$\square,4,8$a s v d d)$2,-5,\square,8,-10$a s v d e)$0.4,-4.3,\square,-4.5,-6.2,-9$a s v d ## Question 11 Answer the following worded questions: a) Trule Inc. records how its profit over$5$years:$\$44,000\quad\$50,000\quad\$12,000\quad\$60,000\quad\$15,000$
What was it's mean annual profit?a s v d

b) Iota Inc. records how its profits/loss over $4$ years:
$\$10,000\quad-\$16,000\quad\$34,000\quad-\$4,000$
Calculate the mean profit/loss over the $4$ years.a s v d