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1. For a continuous random vaniable, the total area beneath the probability dist

ID: 3182039 • Letter: 1

Question


1. For a continuous random vaniable, the total area beneath the probability distribution curve will be greater than zero but less than one. a True b. False 2. The variable in the normal distribution can assume any value from -3.00 to +3.00. a, True b. False 3. The area under the normal curve between z 0 and z is less than the area under the normal curve between z 1 and 2. a. True b. False 4. The standard error of the mean decreases when the sample size decreases. b, False a. True 5. When constructing a confidence interval for the population mean, and the standard deviation of the sample is used, the degrees of freedom for the t-distribution equal n-2. b. False a, True 6. The sample mean (e) is the point estimator of o b, False True 7. As the number of degrees of freedom for a t- distribution increases, the difference between the t distribution and the standard normal distribution (z) becomes smaller. b. False a. True 8. A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is fox) 1/ob a). b. False True 9. Stratified random sampling is a method of selecting a sample in which the sample is first divided into strata, and then random samples are taken from each stratum. a. True b. False

Explanation / Answer

6) False

The sample mean is point estimator of population mean

20)

n =49 , mean = 15.8 , std. deviation = 3.85

z value at 90% confidence interval = 1.645

CI = mean +/- z * SE

= 15.8 + /- 1.645 * ( 3.85 / sqrt(49))

= (14.89 , 16.70)

Answer is option b)

21)

std. deviation = 8 , n = 4

standard error = std. deviation / sqrt(n)

= 8 / sqrt(4)

= 4

Answer is option b)

24)  As n approaches infinity () the t distribution approaches the standard normal distribution.

Answer is option d)