Biology Forums - Study Force

Define the terms stratified sampling, systematic sampling and cluster sampling. Give examples for each.
 
  What will be an ideal response?

Q. 2

Quantitative variables classify individuals in a sample according to
 
  A) personality characteristic. B) numerical measure.
  C) physical attribute. D) exhibited trait.

Q. 3

A seed company has a test plot in which it is testing the germination of a hybrid seed. They plant 50 rows of 40 seeds per row. After a two-week period, the researchers count how many seed per row have sprouted.
 
  They noted that least number of seeds to germinate was 33 and some rows had all 40 germinate. The germination data is given below in the table. The random variable x represents the number of seed in a row that germinated and P(x) represents the probability of selecting a row with that number of seed germinating. Determine the mean number of seeds per row that germinated.
 
  x 33 34 35 36 37 38 39 40
  P(x) 0.02 0.06 0.10 0.20 0.24 0.26 0.10 0.02
 
  A) 0.13 B) 36 C) 36.5 D) 36.9

Q. 4

The forced vital capacity (FVC) is often used by physicians to assess a person's ability to move air in and out of their lungs. It is the maximum amount of air that can be exhaled after a deep breath.
 
  A researcher wants to perform a hypothesis test to determine whether the mean forced vital capacity for adults who are smokers is less than the mean forced vital capacity for adults who are former smokers. He will use a paired sample to determine whether forced vital capacity increases, on average, when adults stop smoking. Identify the variable for the proposed hypothesis test.
  A) Difference between mean forced vital capacity of smokers and mean forced vital capacity of former smokers
  B) Forced vital capacity
  C) Amount of time since person stopped smoking
  D) Number of cigarettes smoked per day
 
  Provide an appropriate response.

Q. 5

The number of hours needed by sixth grade students to complete a research project was recorded with the following results.
 
  Hours Number of students (f)
   4 22
   5 16
   6 16
   7 13
   8 14
   9 8
  10+ 5
 
  A student is selected at random. The events A and B are defined as follows.
 
  A = the event the student took between 6 and
   9 hours inclusive
  B = the event the student took at most 7 hours
 
  Determine the number of outcomes that comprise the event (A or B).
  A) 118 B) 29 C) 51 D) 89

Q. 6

Several watch-dog consumer groups have criticized the fast food industry for serving food with excessive fat content. One watch-dog announced that it will randomly select one fast food chain per week.
 
  The watch-dog will then decide, as a group, to purchase one item off the menu that has been advertised the most on television and in the newspapers. The watch-dog will then have that heavily-advertised, just-purchased item professionally sampled for fat content. Weekly results will be posted on the watch-dog's website. For this scenario, what best describes the watch-dog's sampling activities each week?
  A) Multistage sampling B) Stratified sampling
  C) Systematic sampling D) Cluster sampling

Q. 7

A random number generator is set to generate single digits between 0 and 9. One hundred and fifty random numbers are generated.
 
  The probability distribution for this random number generator is given below. What is the mean of this distribution?
 
  x 0 1 2 3 4 5 6 7 8 9
  P(x) 0.09 0.12 0.11 0.08 0.09 0.13 0.10 0.07 0.10 0.11
 
  A) 6.6 B) 4.5 C) 7 D) 5

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