Statistics Quiz 4

The sample standard deviation is denoted by:

• sigma
• miu
• s
• s^2

The area under a probability distribution is

• positive
• equal to 1
• equal to 0
• negative

If a variable is normally distributed around the mean of 10 with s=2, the probability of getting a value between 8 and 12 is:

• ~68%
• ~95%
• 0.5
• 1

For a bilaterally symmetric risk of 10%, the confidence level is:

• 0.8
• 0.9
• 0.95
• 1

If we want to estimate the population mean and we know the population standard deviation, we use the distribution:

• Normal
• Student
• Chi-squared
• Uniform

The Chi-square distribution is used to estimate:

• Population mean (known variance)
• Population mean (unknown variance)
• Population variance
• Sample variance

For a sample of 12 values, the number of degrees of freedom is:

• 10
• 11
• 12
• 13

The probability of obtaining a value less than 5 for a normally distributed variable around the mean of 5 and sigma=2, is:

• 1
• 0.25
• 0.68
• 0.5

We use the Student distribution for:

• estimating the population mean when we know the variance
• estimating the population mean when we don't know the variance
• estimating the population variance
• estimating the standard deviation

On a Chi-square distribution, a value of "-2" is:

• impossible
• very likely
• high
• more likely than 50%