Reference no: EM13785211

Question 1

1. FOR THIS AND THE NEXT 2 QUESTIONS. Consider the following scenario. Suppose you work for a pharmaceutical firm as a sales rep. Your region is Sub-Saharan Africa where you are currently on a visit to assess the growing market potential for your product, a new drug that treats myocardial infarction (aka heart attack, often, the result of a coronary artery disease). Your firm's drug is particularly effective among individuals aged 60 and older. You are interested in this population. Your company's interest is motivated by two published medical research.

In a 2012 study by Kivimäki et al, they found that smoking appears to be the cause of 36% of coronary artery disease and obesity 20% ("Job strain as a risk factor for coronary heart disease: a collaborative meta-analysis of individual participant data," The Lancet 380, 9852: 1491-7, August 31, 2012). In an earlier study published in 2005, Yusuf et al found that obesity, defined by a body mass index (BMI) of more than 30 kg/m², is a growing phenomenon in Africa where the mean BMI is 26.7. While lower than in North America (BMI = 27.7), it is higher than in all the sub-regions of Asia where BMI as low as 24.0 can be found ("Obesity and the risk of myocardial infarction in 27,000 participants from 52 countries: A Case-Control Study," The Lancet, Volume 366, Issue 9497, 5-11 November 2005, Pages 1640-1649). Note that in all of these studies, the researchers drew their conclusions from working samples.

From these studies, which of the following may be considered a variable that can have a probability distribution? [I] Percentage of Sub-Saharan Africans that smoke [II] Percentage of all Sub-Saharan Africans considered obese [III] Percentage of coronary artery disease cases, in the surveyed group, caused by smoking [IV] Percentage of coronary artery disease cases, in the surveyed group, caused by obesity [V] Mean BMI of all Africans aged 60 years and older [VI] Mean BMI of a group of 100 Africans aged 60 years and older

		I, III, III
		III, IV, VI
		II, III, V
		I, II, V
		IV, V, VI
		All are correct

1 points  

Question 2

1. From the studies, which of the following is NOT a point estimate?

		20%
		36%
		BMI of 26.7
		BMI of 27.7
		BMI of 30.0
		All are point estimates

1 points  

Question 3

1. Which of the following is considered a POPULATION PARAMETER? [I] Percentage of Sub-Saharan Africans that smoke [II] Percentage of all Sub-Saharan Africans considered obese [III] Percentage of coronary artery disease cases, in the surveyed group, caused by smoking [IV] Percentage of coronary artery disease cases, in the surveyed group, caused by obesity [V] Mean BMI of all Africans aged 60 years and older [VI] Mean BMI of a group 100 Africans aged 60 years and older

		I, III, III
		III, IV, VI
		II, III, V
		I, II, V
		IV, V, VI
		All are correct

1 points  

Question 4

1. Which of the following is true about an estimator?

		An estimator is a parameter describing a population
		An estimator is a sample statistic used for estimating a population parameter
		An estimator is does not have a distribution
		None of the above

1 points  

Question 5

1. Suppose X is a normal random variable with mean 10 and standard deviation 4. The probability that X (caution: not x-bar!) will be greater than 12 is

		0.1915
		0.50
		0.3085
		None of the above

1 points  

Question 6

1. Which of the following statements is true for a binomial distribution? [I] Each outcome is dependent on the previous outcome [II] Outcomes are mutually exclusive. [III] Probability of success remains the same from trial to trial. [IV] The outcome of a trial depends on the total number of trials. [V] The probability of failure changes with each subsequent trial.

		I, II, V
		III, IV, V
		II, III *
		IV, V
		All are true
		None is correct

1 points  

Question 7

1. Which of the following statements is true about the distribution of a normal variable? [I] Symmetric about the mean [II] Bell-shaped curve [III] Area under the curve is always one [IV] It is a continuous probability distribution [V] probability that x is equal to a specific value is zero. Please choose the most comprehensive answer.

		I, III, V
		II, III, IV, V
		III, IV, V
		All are true
		None is correct

1 points  

Question 8

1. A new shampoo is introduced in the market. The manufacturer interviews 25 different individuals for their opinion. Eighteen individuals like the shampoo. Compute a point estimate for the proportion of the population that likes the shampoo.

		0.25
		0.72
		0.18
		None of the above
		Incomplete information

1 points  

Question 9

1. A certain brand of electric bulbs has an average life of 300 hours with a standard deviation of 25. A random sample of 64 bulbs is tested. What is the probability that the sample mean (x-bar) will be less than 295?

		0.4452
		0.0548
		0.5
		None of the above

1 points  

Question 10

1. The quality control manager of a local company is sampling for the PROPORTION of defective items in a large shipment. It is known that the population proportion (P) is 0.17. She takes a sample of 200 items. What is the probability that the sample proportion (p-hat) will be AT LEAST 0.22?

		0.22
		0.4699
		0.0301
		None of

1 points  

Question 11

1. The variance of a random variable is:

		always positive
		always negative
		sometimes positive and sometimes negative
		depends on the mean of the random variable

1 points  

Question 12

1. An estimator that contains all the information about the parameter it estimates is to said to be:

		unbiased
		biased
		efficient
		consistent
		sufficient

1 points  

Question 13

1. When the probability that an estimator is close to the parameter it estimates increases as the sample size, n, increases, that estimator is said to be:

		unbiased
		biased
		efficient
		consistent
		sufficient

1 points  

Question 14

1. Given a normally distributed population with mean of 100 and a standard deviation of 20, find P(96 ≤ x-bar ≤ 108). Sample size is 16.

		0.4452
		0.2881
		0.7333
		None of the above

1 points  

Question 15

1. If the uric acid values in normal adult males are approximately normally distributed with a mean and standard deviation of 5.7mg and 1mg, respectively, find the probability that a sample of size 9 will yield a mean less than 5.2.

		0.4332
		0.8664
		0.067
		None of the above

1 points  

Question 16

1. It is known that 35% of the members of a certain population suffer from one or more chronic diseases. What is the probability that in a sample of 200 subjects drawn at random from this population 80 or more will have at least one chronic disease? Note, this problem is about SAMPLE PROPORTION.

		0.40
		0.0694
		0.4306
		None of the above

1 points  

Question 17

1. When sampling is done from a population with population proportion p = 0.10, using a sample size n = 2, what is the sampling distribution of p-hat? Caution! Note the small sample

		Normal
		Binomial
		Poisson
		Hypergeometric
		Not clear what the distribution should be

1 points  

Question 18

1. When sampling is done from a population with population proportion p = 0.10, using a sample size n = 12, is it possible to approximate the sampling distribution of p-hat using the normal distribution?

		Yes, because p-hat is a continuous random variable
		Yes, the Central Limit Theorem does apply for all cases of the sample proportion
		No, since np = 1.2, the Central Limit Theorem does not apply and we cannot use the normal distribution
		None of the above