Researchers collected samples of water from streams in a mountain range to investigate the effects of acid rain. They measured the pH?(acidity) of the water and classified the streams with respect to the kind of substrate?(type of rock over which they?flow). A lower pH means the water is more acidic. The plot to the right shows the pH of the streams by substrate?(limestone, mixed, or?shale). Selected parts of a software analysis comparing pH of streams with mixed and shale substrates are shown below. Complete parts a through c.

?2-Sample t-test of ?1??2=?0, ??Difference Between Means=0.195

?t-Statistic=0.15 ?w/134 ?df,???P=0.8810

6.4

6.8

7.2

7.6

8.0

pH

SubstrateType

L

M

S

Three vertical boxplots, each labeled with a substrate type, are shown side-by-side in a graph with vertical axis labeled "pH" from 6.4 to 8.0 plus in intervals of 0.4. The components of each boxplot have vertical coordinates as follows, listed here from bottom to top: "L," one outlier at 6.4, minimum 6.8, first quartile 7.5, median 7.8, third quartile 8.0, maximum 8.2; "M," unmarked minimum, first quartile 7.0, median 7.2, third quartile 7.5, maximum 7.8; "S," minimum 7.5, first quartile 6.8, unmarked median, third quartile 7.1, maximum 7.3, one outlier at 7.6.

?a) State the null and alternative hypotheses for this test. Choose the correct answer below.

A.

H0?: ?M??S??0; HA?: ?M??S

B.

H0?: ?M??S??0; HA?: ?M??S=0

C.

H0?: ?M??S=?0; HA?: ?M??S?0

D.

H0?: ?M??S??0; HA?: ?M??S>0

?b) From the information you?have, do the assumptions and conditions appear to be?met?

Which of the following conditions are satisfied for the given?data? Select all that apply.

A.

Nearly normal condition

B.

Independent group assumption

C.

Independence assumption

?c) What conclusion would you?draw?

Reject/Fail to reject H0. There is not/is strong evidence that the streams with mixed substrates have mean pH levels different from those of streams with shale substrates.

0 Researchers collected samples of water from streams in a mountain range to investigate the effects of acid rain. They measured the pH (acidity) of the water and classied the streams with respect to the kind of Q substrate (type of rock over which they ow). A lower pH means the water is more acidic. The plot to the right shows the pH of the streams by substrate (limestone, mixed, or shale). Selected parts of a sottware analysis comparing pH of streams with mixed and shale substrates are shown below. Complete parts a through c. M Q 2-Sample Nest of p1 - p2 = 0, Di'erenoe Between Means = 0.195 7 o tStatistic= 0.15 w/134 df, P = 0.3310 In 72 i m 6.8 6.4 . L M s Substrate Type a) State the null and alternative hypotheses for this test. Choose the correct answer below. 0 A. \"aimPS\"; \"Aim"8'0 O B H0:pMps0; HNPM'PS' O D. \"0: PM 'Ps 50? HA: PM 'Ps >0 D) From the information you have, do the assumptions and conditions appear to be met? Which of the following conditions are satised for the given data? Select all that apply. A. Neay normal condition B. Independent group assumption C. Independence assumption c) What conclusion would you dram H0. There l: strong evidence that the streams with mixed substrates have mean pH levels different from those of streams with shale substrates. Click to select your answer(s)