Question

7. Determine whether a normal distribution or a normal distribution or t distribution should be used or whether neither of should be used to construct a confidence interval for the mean. (Section 6.2) Circle the correct answer. in a random sample of 22 families, the mean weekly food expense was $95.60 with a sample standard deviation of $22.50. Assume the weekly food expense is normally distributed. A) Normal distribution B) t-distribution C) Neither For a sample of 20 IQ scores the mean score is 105.8. The sample standard deviation, s, is 15. A) Normal distribution B) t-distribution C) Neither A random sample of 40 college students has mean earnings of $3120 with a population standard deviation, o, of $677 over the summer months. A) Normal distribution B) t-distribution C) Neither A random sample of 15 statistics textbooks has a mean price of $105 with a standard deviation, o, of $30.25. A) Normal distribution B) t-distribution C) Neither In a random sample of 28 apartments, the mean rent was $1500 with a standard deviation, o, of $150. Assume the rent is normally distributed. A) Normal distribution B) t-distribution C) Neither

Answer 1

Solution:

The normal distribution is used if the population standard deviation is known and if the sample size is less than 30 then the population under consideration should be normally distributed. The t-distribution is used if the population standard deviation is unknown and if the sample size is less than 30 then the population under consideration should be normally distributed.

7. Determine whether a normal distribution or these should be used to construct a co Circle the correct answer. ra normal distribution or t distribution should be used or whether neither of be used to construct a confidence interval for the mean. (Section 6.2) "a random sample of 22 families, the mean weekly food expense was $95.60 with a sample standard deviation of $22.50. Assume the weekly food expense is normally distributed A) Normal distribution |B) t-distribution C) Neither Population standard deviation is unknown For a sample of 20 IQ scores the mean score is 105.8. The sample standard deviation, s, is 15. A) Normal distribution B) t-distribution C) Neither We don't know if the IQ scores are normally distributed or not A random sample of 40 college students has mean earnings of $3120 with a population standard deviation.o.of $677 over the summer months. A) Normal distribution B) t-distribution C) Neither Standard deviation known and sample size >30 A random sample of 15 statistics textbooks has a mean price of $105 with a standard deviation, o, of $30.25. A) Normal distribution B) t-distribution (C) Neither We don't know if the prices of statistics textbooks is normally distributed or not In a random sample of 28 apartments, the mean rent was $1500 with a standard deviation of $150 Assume the rent is normally distributed. A) Normal distribution (B) t-distribution C) Neither Known standard deviation and normally distributed