Question

The price per share of stock for a sample of 25 companies was recorded at the beginning of a given year and then again at the end of the 1st quarter of that year. How stocks perform during the 1st quarter is an indicator of what is ahead for the stock market and the economy. Use the sample data given below to answer the following.

Company	End of 1st Quarter	Beginning of Year
Company A	24.13	19.91
Company B	39.01	37.36
Company C	51.9	45.78
Company D	58.42	62.03
Company E	66.96	65.58
Company F	106.48	105.94
Company G	29.01	23.71
Company H	12.45	10.71
Company I	44.41	41.22
Company J	21.07	17.91
Company K	30.23	30.24
Company L	20.15	18.08
Company M	51.31	42.04

Company	End of 1st Quarter	Beginning of Year
Company N	46.98	33.25
Company O	66.21	66.71
Company P	37.23	40.12
Company Q	71.12	62.00
Company R	41.27	41.56
Company S	32.26	25.96
Company T	75.01	69.97
Company U	68.06	54.70
Company V	86.73	84.76
Company W	23.65	21.64
Company X	28.16	25.58
Company Y	108.21	106.40

(a)

Let

d_i

denote the change in price per share for company i where

d_i

= price per share at the end of the 1st quarter of the given year minus price per share at the beginning of that year. Use the sample mean of these values to estimate the dollar amount a share of stock has changed during the 1st quarter. (Round your answer to two decimal places.)

$

(b)

What is the 95% confidence interval (in dollars) estimate of the population mean change in the price per share of stock during the first quarter? (Use end of first quarter − beginning of year. Round your answers to two decimal places.)

$  to $

Interpret this result.

The 95% confidence interval  ---Select--- is completely below is completely above contains zero. This shows that the population mean price per share of stock has  ---Select--- decreased increased over the three-month period.

Answer 1