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Multiple Choice Questions in Statistics: Farm Surveys and Data Analysis, Exams of Data Analysis & Statistical Methods

Utah State University (USU)Data Analysis & Statistical Methods

Multiple choice questions related to statistics, specifically focusing on a survey of 250 farms in central iowa and the analysis of the collected data. Topics covered include variables in a survey, mean and standard deviation, correlation, and interquartile range.

Typology: Exams

Pre 2010

Uploaded on 08/18/2009

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Part I Miscellaneous multiple choice questions (Total points: 30).
In the following questions, only one answer is completely correct. Circle this correct
answer. (3 points each). Do not circle more than one answer - you will not get points if
you circle more than one answer!
1. A survey of 250 farms in central Iowa asked for the registration number of the farm,
size of the farm in acres, corn yield in bushels of corn per acre, and total number of
people working on the farm. How many variables have been included in the survey?
(a) Three - size of the farm, corn yield, and number of people working on the farm
(b) Four - registration number of the farm, size of the farm, corn yield and number of
people working on the farm
(c) Five - number of farms, registration number of the farm, size of the farm, corn yield,
and number of people working on the farm,
(d) 250
2. The results of the survey in Question 1 show that the distribution of corn yields is
approximately normal with mean 120 and standard deviation 15. The mean with its
proper unit is
(a) 120 bushels
(b) 120 bushel/acre
(c) 120 (no units - it's just a number)
(d) 120 acres
3. The variance of the corn yield in Question 2 is
(a) 30
(b) 225
(c) 240
(d) 14,400
4. From the survey results in Question 2, we can say that about 95% of the surveyed
central Iowa farms have corn yields that are between
(a) 105 and 135 bushel per acre.
(b) 90 and 150 bushel per acre
(c) 75 and 165 bushel per acre
(d) 120 and 345 bushel per acre
pf3
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Download Multiple Choice Questions in Statistics: Farm Surveys and Data Analysis and more Exams Data Analysis & Statistical Methods in PDF only on Docsity!

Part I Miscellaneous multiple choice questions (Total points: 30).

In the following questions, only one answer is completely correct. Circle this correct answer. (3 points each). Do not circle more than one answer - you will not get points if you circle more than one answer!

  1. A survey of 250 farms in central Iowa asked for the registration number of the farm, size of the farm in acres, corn yield in bushels of corn per acre, and total number of people working on the farm. How many variables have been included in the survey? (a) Three - size of the farm, corn yield, and number of people working on the farm (b) Four - registration number of the farm, size of the farm, corn yield and number of people working on the farm (c) Five - number of farms, registration number of the farm, size of the farm, corn yield, and number of people working on the farm, (d) 250
  2. The results of the survey in Question 1 show that the distribution of corn yields is approximately normal with mean 120 and standard deviation 15. The mean with its proper unit is (a) 120 bushels (b) 120 bushel/acre (c) 120 (no units - it's just a number) (d) 120 acres
  3. The variance of the corn yield in Question 2 is (a) 30 (b) 225 (c) 240 (d) 14,
  4. From the survey results in Question 2, we can say that about 95% of the surveyed central Iowa farms have corn yields that are between (a) 105 and 135 bushel per acre. (b) 90 and 150 bushel per acre (c) 75 and 165 bushel per acre (d) 120 and 345 bushel per acre
  1. The analysis of the data collected in the survey found that the correlation between the size of the farm and the corn yield was r = 0.82. This means that (a) there is little or no connection between farm size and the yield per acre of corn on that farm (b) larger farms tend to have lower yields of corn (c) larger farms tend to have higher yields of corn. (d) The average farm plants corn on 82% of its acres.
  2. If you compute that the standard deviation of a set of data is -1.75, you know that (a) the distribution of the data is skewed to the right (b) all data values in the data set are negative (c) there is a negative linear association in the data (d) you made an arithmetic mistake
  3. You receive a fax with 6 bids (in millions of dollars): 0.5, 1.3, 1.9, 1.2, 2.4, and x where x is some number that is too blurry to read. Without knowing what x is, the median (a) is 1. (b) must be between 1.2 and 1. (c) could be any number between 1.2 and 2.
  4. A sample was taken of the salaries of 200 employees from a large company. The following are the salaries (in thousands of dollars) for this year (the data are ordered): 28 31 34 35 37 41 42 42 42 47 49 51 52 52 60 61 67 72 75 77 Suppose each employee in the company receives a $3000 raise for next year (each employee's salary is increased by $ 3000). The interquartile range (IQR) of the salaries will (a) be unchanged (b) increase by $ (c) be multiplied by 3000
  5. All but one of the following statements contain a blunder. Which one does not contain a blunder? (a) The correlation between a position a football player plays and his or her weight is 1.54. (b) The correlation between the amount of fertilizer and yield of tomatoes was found to be r = 0.33. (c) The correlation between body weight and body height in a group of 8 randomly chosen Stat 2000 students is 0.86 lb/inch.

Part I: Multiple choice questions - explanations

  1. a) The variables included in the study are size of the farm, corn yield, and number of people working on the farm. Registration number is the identification of a record (farm) - thus it is not considered a variable. Number of farms is the size of the sample, and 250 is the number of observations.
  2. b) Corn yield is given in bushel/acre - so the mean will also have this unit.
  3. b) The variance is the squared standard deviation - 15 2.
  4. b) When the data are normally distributed, 95% of the observation are between mean ± 2 standard deviation (68 - 95 - 99.7 - rule!)
  5. c) A positive correlation means that the larger values of x are associated with larger values of y - larger farms have higher corn yields.
  6. d) The standard deviation cannot be negative!
  7. b) The median of 6 numbers is the mean of the third and the fourth smallest number. Whatever x is, the median will be either between 1.2 and 1.3 (if x is smaller than 1.2), or between 1.3 and 1.9 (if x is larger than 1.9), or between x and 1.3 (if x is between 1.2 and 1.3 or between 1.3 and 1.9). So the median must be between 1.2 and 1.9.
  8. a) When each number increases by the same amount, the first and the third quartile will increase by the same amount as well, and the interquartile range (the difference between Q 3 and Q 1 ) will be unchanged.
  9. b) The correlation coefficient cannot be larger than 1 and it is unitless.
  10. b) Since there are only two points, they lie exactly on the same line, so that the correlation can be either 1 or -1. Since the larger height is associated with the smaller weight, the correlation must be -1.