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1. Which of the following is not true? options: 2. A farmer investigated pestici

ID: 3182089 • Letter: 1

Question

1. Which of the following is not true?

options:

2. A farmer investigated pesticide contamination at a small pond with significant run-off (meaning water runs from the nearby fields into the pond). Ten measurements of pesticide concentrations were randomly taken at the pond (assume the pesticide is normally distributed throughout the pond). The reported pesticide concentrations: 18.4, 25.8, 27.3, 19.5, 23.8, 29.4, 30.1, 29.1, 33.8 and 35.7 g/L. Given that the data distribution is normal, find the t-value for a 90% confidence level.

options:

3. Which of the following is true about the degrees of freedom?

options:

4.A farmer investigated pesticide contamination at a small pond with significant run-off (meaning water runs from the nearby fields into the pond). Eight measurements of pesticide concentrations were randomly taken at the pond (assume the pesticide is normally distributed throughout the pond). The reported pesticide concentrations: 15.1, 13.2, 15.3, 14.7, 11.0, 15.2, 16.5, 18.1, g/L. Given that the data distribution is normal, find the t-value for a 95% confidence level.

options:

(4 points)

5. A farmer investigated pesticide contamination at a small pond with significant run-off (meaning water runs from the nearby fields into the pond). Ten measurements of pesticide concentrations were randomly taken at the pond (assume the pesticide is normally distributed throughout the pond). The reported pesticide concentrations: 18.4, 25.8, 27.3, 19.5, 23.8, 29.4, 30.1, 29.1, 33.8 and 35.7 g/L. Given that the data distribution is normal, find the t-value for a 95% confidence level.

options:

6. Which of the following is true about the t-distribution?

options:

a) As n approaches infinity, the t-distribution table looks more like the Standard Normal table b) Confidence intervals from the t-distribution are wider than confidence intervals from the normal distribution c) For hypothesis testing the t-distribution gives lower p-values than the normal distribution d) Degree of freedom is not the same as sample size e) The t-statistic has larger variance than the z-statistic

Explanation / Answer

1 ) Option ( b ) is incorrect .

2 ) Required t value for a 90 % confidence level for 9 degrees of freedom = 1.833

The correct option is ( e ) .

3 ) Option ( b ) is correct .

4 ) Number of measurements = 8

Degrees of freedom = 7

Required t value = 2.365

Correct option is ( b ) .

5 ) Number of observations = 10

Degrees of freedom = 9

Required t value = 2.262

Correct option is ( b )

6 ) Option ( a ) is correct .