Surveys
Census
Give two types of survey samples
stratified
random
self-selected
systematic
5000 lizards living on an island. The correct sample size to detect disease is?
sqrt(5000)= 71
you need to round up to go over
From 2000 kangaroos and sample of 77 is taken. Which is the sample
77
A calculator is used to generate random numbers to select from a group
random
On the calculator the correct input for a random number from 1 to 100 is?
a) IntRan(1,100)=
b) RanInt#(1,100)=
c) RanInt(100,1)=
d) IntRan#(1,100)=
RanInt#(1,100)=
Census or sample?
A match box producer tests every fiftieth match box to see if the correct number of matches has been included.
Sample
What type of survey sample?
Every 10th person is chosen from a group
Systematic
A sample of 6 toasters will be surveyed using a systematic sample from a population of 1 to 36 toasters lined up on a factory line. Give the numbers of the first 4 toasters to be tested.
Hint: start with the 1st one
36/6 = 6
Every 6th toaster
1st, 7th, 13th, 19th, 25th, 31st, 37th
Census or Sample?
A school council conducts an election for a new president. Every council member casts a vote.
Census
What type of survey?
The sample makes sure it matches the population using percentages
Stratified
A sample of 20 students was taken from 400 students being at a school, but 60% were boys and 40% were girls. How many boys and girls should be surveyed to keep the sample stratified
12 boys and 8 girls
Can a survey be a sample or a census?
Yes
Self-Selected Or Self-Selecting
A sample of 12 cattle was taken by a person who understands maths. The original population of cattle would have been?
122 = 144