Select the correct answer below: a convenient sample of 23 individuals is taken from the residents of a city with approximately normally distributed commute times. the sample mean is 19 minutes and the sample standard deviation is 2 minutes. o a population is used to obtain a sample mean of 53 and a sample standard deviation of 7 based on a convenien sample of size 19. o a sample mean of 70 and sample standard deviation of 7 are obtained using a simple random sample of size 19 from a normally distributed population. a sample mean of 194 pages and a standard deviation of 37 pages are obtained using a simple random sample of 30 books from a public library having approximately normally distributed numbers of pages. the population standard deviation is 31.4 pages. ous