Question

All questions on this quiz refer to some of the information given here:

Sulfur compounds such as dimethyl sulfide (DMS) cause “off odors” in wine, so winemakers want to know the odor threshold, the lowest concentration of DMS that the human nose can detect. Different people have different thresholds, so we start by asking about the mean threshold in the population of all adults. Scientific research shows that in the population of all adults, this mean is 25 micrograms per liter and the standard deviation is 7 micrograms per liter. Here are the odor thresholds (measured in micrograms of DMS per liter of wine) for 10 randomly chosen subjects

            28        40        28        33        20        31        29        27        17        21

Question 1 (1 point)

Saved

The sample mean is

Question 1 options:

	x̄ = 27.40
	x̄ = 25
	μ = 27.40
	μ = 25

Question 2 (1 point)

Saved

The population mean is

Question 2 options:

	x̄ = 27.40
	μ = 27.40
	x̄ = 25
	μ = 25

Question 3 (1 point)

Saved

The sample standard deviation is

Question 3 options:

s = 7

σ = 7

σ = 6.75

s = 6.75

Question 4 (1 point)

Saved

The population standard deviation is

Question 4 options:

s = 7

σ = 6.75

σ = 7

s = 6.75

Question 5 (1 point)

The value 27.4 is a

Question 5 options:

	parameter
	statistic
	neither a parameter nor a statistic
	both a parameter and a statistic
	none of these

Question 6 (1 point)

The value 25 is a

Question 6 options:

	none of these
	both a parameter and a statistic
	statistic
	neither a parameter nor a statistic
	parameter

Question 7 (1 point)

If we repeatedly take SRS’s of size n = 10 wine tasters and calculate the mean DMS threshold  for each sample, we will find the sampling distribution of x̄  is

Question 7 options:

	exactly Normal, with mean 25 and standard deviation 7.
	uniform,  values will be evenly spread out between 0 and 50.
	cannot be determined until we actually see all possible samples.
	Constant : the value of   x̄  can only be 27.4
	approximately Normal, with mean 25 and standard deviation 2.214

Question 8 (1 point)

The answer to the last question is because of

Question 8 options:

	the Central Limit Theorem
	the Law of Large Numbers
	statistical significance.
	population distribution.

Question 9 (1 point)

One particular study done by a winery plans to start with a (new random) sample of 10 people and test their DMS thresholds. What is the probability that they find a sample mean   x̄  less than 23?

Question 9 options:

	- 0.90
	We cannot tell without more data from another sample.
	50%, because the sample mean must be either larger or smaller than the population mean.
	0.3897
	0, because we already have a sample with x̄ = 27.4
	0.8159
	1, because the last sample had x̄ larger than 25, the next one must have x̄ lower than 25.
	- 0.28
	0.6103
	0.1841

Question 10 (1 point)

One particular study done by a winery plans to start with a (new random) sample of 10 people and test their DMS thresholds. What is the probability that they find a sample mean x̄ greater than 23?

Question 10 options:

	50%, because the sample mean must be either larger or smaller than the population mean.
	- 0.90
	0.8159
	0, because we already have a sample with x̄ = 27.4
	We cannot tell without more data from another sample.
	0.3897
	0.1841
	- 0.28
	1, because the last sample had x̄ larger than 25, the next one must have x̄ lower than 25.
	0.6103

Answer 1