Reference no: EM132483488

1.Data collected by child development scientists produced the following 90% confidence interval for the average age (in months) at which children say their first word: (10.1 months, 13.4 months). Which statement correctly interprets this interval?

a) Based on this sample, we can say, with 90% confidence, that the mean age at which children say their first word is between 10.1 and 13.4 months.

b) 90% of the children in this sample said their first word when they were between 10.1 and 13.4 months old.

c) If we took many random samples of children, about 90% of them would produce this confidence interval.

d) We are 90% sure that a child will say his first word when he is between 10.1 and 13.4 months old.

2.An industrial designer wants to determine the average amount of time it takes an adult to assemble an "easy to assemble" toy. A sample of 16 times yielded an average time of 19.9 minutes, with a sample standard deviation of 6 minutes. Assuming normality of assembly times, provide a 90% confidence interval for the mean assembly time.