Week 1 Quiz

The Palmer penguins field log records n = 344 penguins on three islands of Antarctica's Palmer Archipelago. Which description of these 344 penguins is correct?

Select one.

• A sample from the population of penguins on those islands
• The whole population of penguins living on those three islands
• A parameter that describes the penguin population
• A statistic computed from the whole population

The 342 penguins in the field log with a recorded body mass average 4,201.75 g. How should this 4,201.75 g average be described?

Select one.

• A parameter, because 342 penguins is a large group
• A statistic, because it was computed from a sample
• A parameter, because it describes the body mass of all penguins
• Neither, because an average cannot describe a group

The six faces of a fair die, 1 through 6, are a whole population with N = 6, and their average is 3.5. How should this 3.5 be described?

Select one.

• A statistic, because it is an average of the numbers on the faces
• A statistic, because it comes from only six values
• A parameter, because it describes the whole population
• Neither, because a die face is a category

In the penguin field log, each bird's year of observation is recorded. Which level of measurement fits year?

Select one.

• Nominal, because years are labels for seasons
• Ordinal, because the years come in a natural order from first to last
• Ratio, because year has a true zero
• Interval, because gaps are equal but zero is not none

Which of these penguin field-log variables are categorical? Select all that apply.

Select every option that applies.

• species
• body mass (g)
• island
• flipper length (mm)
• sex

A researcher codes the penguin species as 1 for Adelie, 2 for Chinstrap, and 3 for Gentoo, then reports the average species code for the field log. What is wrong with that average?

Select one.

• Species is nominal, so an average of its codes means nothing
• The codes should start at 0 so the average is correct
• The average should be rounded to the nearest code
• Nothing is wrong, because the codes are numbers

A follow-up team will revisit 43 of the 344 logged penguins with a systematic sample: a random start, then every k-th bird on the list. What step k should the team use? Enter a whole number.

Type a short answer.

The field log has 152 Adelie, 68 Chinstrap, and 124 Gentoo penguins. A stratified plan revisits one in every 4 birds from each species, 86 birds in all. How many Gentoo penguins does the plan revisit? Enter a whole number.

Type a short answer.

An online store's product page shows a rating built from thousands of customer reviews that customers chose to write. Which statement about that rating is correct?

Select one.

• It is accurate, because thousands of reviews remove any bias
• It is a simple random sample, because no customer was singled out
• It can still be biased, because more of the same reviews keep the lean
• It is a parameter, because it includes every review written

Because all 124 Gentoo penguins in the field log were recorded on Biscoe, the field log shows that living on Biscoe causes a penguin to be a Gentoo.

True or false.

• True
• False