# Question

Let X and Y equal the hardness of the hot and cold water, respectively, in a campus building. Hardness is measured in terms of the calcium ion concentration (in ppm). The following data were collected (n = 12 observations of X and m = 10 observations of Y):

(a) Calculate the sample means and the sample variances of these data.

(b) Construct a 95% confidence interval for μX − μY, assuming that the distributions of X and Y are N(μX, σ2X) and N(μY, σ2Y), respectively.

(c) Construct box plots of the two sets of data on the same graph.

(d) Do the means seem to be equal or different?

(a) Calculate the sample means and the sample variances of these data.

(b) Construct a 95% confidence interval for μX − μY, assuming that the distributions of X and Y are N(μX, σ2X) and N(μY, σ2Y), respectively.

(c) Construct box plots of the two sets of data on the same graph.

(d) Do the means seem to be equal or different?

## Answer to relevant Questions

Let S2X and S2Y be the respective variances of two independent random samples of sizes n and m from N(μX, σ2X) and N(μY, σ2Y). Use the fact that F = [S2Y/σ2Y]/[S2X/σ2X] has an F distribution, with parameters r1 = m− ...A candy manufacturer selects mints at random from the production line and weighs them. For one week, the day shift weighed n1 = 194 mints and the night shift weighed n2 = 162 mints. The numbers of these mints that weighed at ...If Y1/n and Y2/n are the respective independent relative frequencies of success associated with the two binomial distributions b(n, p1) and b(n, p2), compute n such that the approximate probability that the random interval ...Find 95% confidence intervals for α, β, and σ2 for the predicted and earned grades data in Exercise 6.5-4. In Exercise 6.5-4 The following 54 pairs of data give, for Old Faithful geyser, the duration in minutes of an eruption and the time in minutes until the next eruption: (a) Calculate the correlation coefficient, and construct a scatterplot, of ...Post your question

0