Estimating Population Mean and Margin of Error

The sample size of poll is 107 people. What is the approximate margin of error.

• 10%

• 3.1%

• 2.38%

• 1%

As a data scientist you have been asked to compare the difference of two percentages within the same survey. Which margin of error rule would you use?

To cut the margin of error in half, the sample size would have to increase by ______________.

• 100

• 2 times

• 3.1%

• 4 times

A survey of 400 people is done, what is the approximate margin of error.

• 5%

• 3.1%

• 20%

• 10%

• If the proportion of old people wearing dentures is greater than 60%.

• If the proportion of old people wearing dentures is 61%.

• If the proportion of old people wearing dentures is more than 65%.

• If the proportion of old people wearing dentures is 65%.

Of 900 surveyed New Zealanders, the proportion of Labour supporters is 45% and for National it is 38% (undecideds are ignored). The difference between these two percentages is 7 perc pts. Can the claim that more NZers support Labour be made?

• Yes, because the Confidence Interval is [0.4 perc pts , 13.6 perc pts] and is greater than 0 perc pts. This means that support for labour could be as low as 0.4 perc pts more than National to as much as 13.6 perc pts more than National.

• Yes

• Yes, because the Confidence Interval is [3.7 perc pts , 10.3 perc pts] and it is greater than 0 perc pts.This means that support for labour could be as low as 3.7 perc pts more than National to as much as 10.3 perc pts more than National.

• No, the sample of New Zealanders is too small.

In a single survey, 150 men and 350 women were interviewed about their movie viewing habits. Which is the most appropriate Margin of error rule to use for comparing the two groups?

A survey (n=500) was carried out to identify male and female movie habits. They interviewed 150 men and 350 women. 53% of men said they preferred action movies and 49% of women said they preferred action movies.

Can the claim "More men liked action movies" be made ?

• Yes, men who prefer action movies are 4 perc. pts greater than females.

• Yes, because the CI = [ 0.9 perc pts , 7.1 perc pts ]. The percentage of men could be 0.9 perc pts higher to as much as 7.1 perc pts higher.

• No, because the CI = [ -4.9 perc pts , 12.9 perc pts ]. The percentage of men could be 4.9 perc pts lower, possibly equal or as much as 12.9 perc pts higher.

• No, because the CI = [ -9.7 perc pts , 17.7 perc pts ]. The percentage of men could be 9.7 perc pts lower, possibly equal or as much as 17.7 perc pts higher.