Lab 7: Confidence Intervals and Hypothesis Testing (Part 1)

Purpose: To become familiar with R functionality for computing confidence intervals and conducting hypothesis tests.

EXERCISE

(1) Compute a 95% confidence interval for the true mean lead content in the Sebring, OH

water system.

(2) Build an 80% confidence interval for the mean lead concentration in the Sebring, OH

water supply. Use the t.test function.

(3) Conduct a hypothesis test that the proportion of minority visitors to Great Smokey

Mountains National Park (GSMNP) is also 13%. A survey of visitors showed 1,221

minorities out of 10,248 visitors.

(4) Build a 99% confidence interval for the proportion of minority visitors to Great

Smokey Mountains National Park (GSMNP). A survey of visitors showed 1,221 minorities

out of 10,248 visitors.

(5) Redo Exercise 3, but using binom.test. Comment on any differences in the results

between prop.test and binom.test in terms of the hypothesis test and the confidence

interval.

flint sebring 0.082 0.017 0.082 0.024 0.003 0.007 0.035 0.016 0.003 0.051 0.041 0.039 0.031 0.025 0.02 0.014 0.005 0.032 0.036 O 0.038 0.048 0.052 0.003 0.029 0.029 0.005 0.043 0.018 0.011 0.058 0.01 0.054 0.001 0.025 0.009 0.027 0.001 0.025 0.049 0.081 0.037 0.008 0.057 0.009 0.027 0.029 0.054 0.001 0.001\f0.012 0.04 0.002 0 0.022 0.032 0.013 O 0.021 0.05 0.013 0.054 0.029 0.025 0.003 0.05 0.078 0.038 0.014 0.022 0.034 0.027 0.001 0.002 0.042 0.053 0.001 0.028 0.003 0.002 0.05 0.024 0.055 0.001 0.018 0.04 0.016 0.017 0.009 0.059 0.002 0.008 0.048 0.039 0.001 0.02 0.092 0.003 0.003 0.001 0.003 0.0040.001 0.001 0.002 0.007 0.007 0.004 0.021 0.026 0.005 0.013 0.074 0.042 0.004 0.012 0.017 0.018 0.002 0.01 0.07 0.033 0.061 0.008 0.045 0.038 0.029 0.043 0.025 0.047 0.013 0.022 0.045 0.012 0.069 0.007 0.013 0.004 0.016 0.05 0.012 0.016 0.056 0.002 0.088 0.004 0.043 0.01 0.03 0.024 0.053 0.029