Question

A botanist wishes to estimate the typical number of seeds for a certain fruit. She samples 59 specimens and counts the number of seeds in each. Use her sample results (mean = 18.2, standard deviation = 14.8) to find the 90% confidence interval for the number of seeds for the species. Enter your answer as an open-interval (i.e., parentheses) accurate to 1 decimal place.  

90% C.I. = ________

Answer 1

Solution :

t _/2,df = 1.671

Margin of error = E = t_/2,df * (s /n)

= 1.671 * (14.8 / 59)

Margin of error = E = 3.2

The 90% confidence interval estimate of the population mean is,

- E < < + E

18.2 - 3.2 < < 18.2 + 3.2

15.0 < < 21.4

(15.0 , 21.4)