In early 2009 the economy was experiencing a recession. But how was the recession affecting the stock market? Shown are the data from a sample of 15 companies. Shown for each company is the price per share of stock on January 1 and April 30 (The Wall Street Journal, May 1, 2009)
DATA:
COMPANY JANUARY 1 ($) APRIL 30 ($)
Applied Materials 10.13 12.21
Bank of New York 28.33 25.48
Chevron 73.97 66.10
Cisco Systems 16.30 19.32
Coca-Cola 45.27 43.05
Comcast 16.88 15.46
Ford Motors 2.29 5.98
General Electric 16.20 12.65
Johnson & Johnson 59.83 52.36
JP Morgan Chase 31.53 33.00
Microsoft 19.44 20.26
Oracle 17.73 19.34
Pfizer 17.71 13.36
Philip Morris 43.51 36.18
Procter and Gamble 61.82 49.44
a. What is the change in the mean price per share of stock over the 4-month period?
b. Provide a 90% confident interval estimate of the change in the mean price per share of stock. Interpret the results.
c. What was the percentage change in the mean price per share of stock over the 4-month period?
d. If this same percentage change were to occur for the next 4 months and again for the 4 months after that, what would be the mean price per share of stock at the end of the year 2009?