An article gave a scatter plot along with the least squares line of x = rainfall volume (m³) and y = runoff volume (m³) for a particular location. The accompanying values were read from the plot.

x	4	12	14	16	23	30	40	47	55	67	72	83	96	112	127
y	4	10	13	15	15	25	27	48	38	46	53	72	82	99	100

(b) Calculate point estimates of the slope and intercept of the population regression line. (Round your answers to four decimal places.)

slope
intercept

(c) Calculate a point estimate of the true average runoff volume when rainfall volume is 51. (Round your answer to four decimal places.) m³ (d) Calculate a point estimate of the standard deviation . (Round your answer to two decimal places.) m³ (e) What proportion of the observed variation in runoff volume can be attributed to the simple linear regression relationship between runoff and rainfall? (Round your answer to four decimal places.)

2.A report included the following information on the heights (in.) for non-Hispanic white females.

Age	Sample Size	Sample Mean	Std. Error Mean
20-39	865	65.9	0.09
60 and older	935	64.3	0.11

(a)Calculate a confidence interval at confidence level approximately 95% for the difference between population mean height for the younger women and that for the older women. (Use_{20-3960 and older}.)

,

Carry out a test of these hypotheses at significance level 0.001. Calculate the test statistic and determine the P-value. (Round your test statistic to two decimal places and your P-value to four decimal places.)z=P-value=