1)For this situation, classify thegiven percent? Based on the 2000 Census, 31.5% of the Australian population who are over 5 years old speak languages other than English at home.

Select one:

a.Parameter

b.Both statistic and parameter

c.Neither statistic or paramter

d.Statistic

2) In a survey of eating habits, 3800 national adults were selected randomly and contacted by telephone. Respondents were asked, "Typically, how many times per week do you purchase food at a fast-food restaurant or convenience store?" On average, those surveyed purchased food at a fast-food restaurant or convenience store 2.4 times per week.

Suppose the researchers that conducted the survey described above decide to conduct it again, but will now interview only 2200 people. In the first survey, their sample average value was 2.4. Which of the following is true about the sample average value for the second survey?

Select one:

a.By the law of large numbers, the smaller (second) survey will certainly produce a sample average farther from the true population average than the larger (first) survey.

b.By the law of large numbers, it would again be 2.4.

c.A different value for the sample average may result as sample averages (as estimates of the population value) are variable.

d.The average income computed from the sample of 1000 people would be more accurate because smaller samples tend to be more homogeneous than larger samples.

3)The average age of residents in a large residential retirement community is 69 years with standard deviation 5.8 years. A simple random sample of 100 residents is to be selected, and the sample mean ageof these residents is to be computed.

Reference: Ref 10-3

We know the random variablehas approximately a normal distribution because of

Select one:

a.the 68-95-99.7 rule.

b.the population we are sampling from has a Normal distribution.

c.the central limit theorem.

d.the law of large numbers.

4) In a large population of college-educated adults, the mean IQ is 118 with standard deviation 20. Suppose 200 adults from this population are randomly selected for a market research campaign.

The distribution of the sample mean IQ is

Select one:

a.approximately Normal, mean equal to the observed value of the sample mean, standard deviation 20.

b.exactly Normal, mean 118, standard deviation 20.

c.approximately Normal, mean 118, standard deviation 1.414.

d.approximately Normal, mean 118, standard deviation 0.1.

5) For which of the following situations would the Central Limit Theorem for Sample Means NOT apply?

Select one:

a.A random sample of size 20 is drawn from a bell-shaped population.

b.A random sample of size 20 is drawn from a skewed population.

c.A random sample of size 50 is drawn from a skewed population.

d.A random sample of size 50 is drawn from a bell-shaped population.

6)The sampling distribution of a statistic is

Select one:

a.the probability that we obtain the statistic in repeated random samples.

b.the extent to which the sample results differ systematically from the truth.

c.the distribution of values taken by a statistic in all possible samples of the same size from the same population.

d.the mechanism that determines whether randomization was effective.

7)Nationwide, the amount charged by doctors for performing a particular minor surgical procedure averages $1220 and varies with a standard deviation of $270. We randomly select 140 bills from the population of all bills charged for this surgery. Letrepresent the average amount charged for these 140 surgical procedures.

Reference: Ref 10-6

The mean and standard deviation of the sample averages,, are

Select one:

a.mean = $1220 and standard deviation = $270.

b.mean = $1220 and standard deviation = $22.82.

c.mean = $122 and standard deviation = $22.82.

d.mean = $122 and standard deviation = $270

8)onsider a random sample with sample mean,XX

. If the sample size is increased from n = 40 to n = 360, then the standard deviation ofthe sampling distribution of sample means,XX

, will

Select one:

a.decrease by a factor of 9 (will be multiplied by 1/9).

b.decrease by a factor of 3 (will be multiplied by 1/3).

c.remain the same.

d.increase by a factor of 9 (will be multiplied by 9).

9) Suppose that the weight of apples eaten in a year by individual Australians can be described by a normal probability distribution with mean = 6.8 kg and standard deviation = 2.4 kg per year. For a random sample of n = 9 people, what is the standardised score, z-statistic,for a sample mean,XX= 7.2 kg? Give your answer to ONLY one (1) decimal place.

10)The incomes in a certain large population of college teachers have a normal distribution with mean $75,000 and standard deviation $10,000. Four teachers are selected at random from this population to serve on a committee. What is the probability that their average salary is less than $65,000?

[Hint: firstly consider the standardised z-statistic for the sample]

Select one:

a.essentially 0

b.0.9772

c.0.1587

d.0.0228