Question

A stock market analyst wants to determine if the recent introduction of the IPhone 8x has changed the distribution of shares in the cellphone market. The analyst collects data from a random sample of 300 cellphone customers. The table below shows the observed customers’ share of cellphones (fi ). When using this random sample, the analyst needs to be 95% confident of test results. The hypothesis to be tested follows:

H0 : Plg =0.20; Pa =0.32; Ps =0.48 ; market shares have remained same

Ha : Plg ≠0.20; Pa ≠0.32; Ps ≠0.48 ; market shares have changed

Cellphone company	Current Market Share	Observ. fi
Samsung	0.48	100
Apple	0.32	120
LG	0.20	80
Totals		300

a.Compute the test statistic for a chi-squared test.

b. After the test, would you conclude that the introduction of the IPhone 8x has changed the market composition? Why?

Answer 1

ex-Ans) To test hypothesion HO: Plq=0.2 PA=0.32, Ps= 0.48 market shares have remained same VS Hi Plq+0.2 , Pato.32, Pst 0.48 Market shaxos have changed observed 100 Company | Moucket Samsung 0.08 Apple 0.32 LG 0.20 Totals 120 expected 0:48X300 - 19 0.32x800 = 96 0.2 X 300 = 60 300 Boo Test statistics Xeal: 5 (01-Fi)? (100-14492 + (120-96)2 + (80-6012 144 - 13.44 + 6 + 6.67 Xea = 26.11 Dection Rule 8 - Reject Hopf p-value (420.05 96 p-value = P[ Xhuy Xeou] =P[X²3-17 26.11] from ² table IP-value - 0.0000 Deeltion - Here pvalle ed=0.05 it Ho at a:0:05 conclusion it may be conclude that the o introduction of the iphone x has changed the macked composition.