A random sample of 390 married couples found that 284 had two or more personality preferences in common. In another random sample of 572 married couples, it was found that only 32 had no preferences in common. Let p1 be the population proportion of all married couples who have two or more personality preferences in common. Let p2 be the population proportion of all married couples who have no personality preferences in common. (a) Find a 90% confidence interval for p1 – p2. (Use 3 decimal places.) lower limit =__ upper limit =__ The U.S. Geological Survey compiled historical data about Old Faithful Geyser (Yellowstone National Park) from 1870 to 1987. Let x1 be a random variable that represents the time interval (in minutes) between Old Faithful eruptions for the years 1948 to 1952. Based on 9440 observations, the sample mean interval was x1 = 63.6 minutes. Let x2 be a random variable that represents the time interval in minutes between Old Faithful eruptions for the years 1983 to 1987. Based on 24,053 observations, the sample mean time interval was x2 = 72.8 minutes. Historical data suggest that ?1 = 8.21 minutes and ?2 = 12.62 minutes. Let ?1 be the population mean of x1 and let ?2 be the population mean of x2. (a) Compute a 95% confidence interval for ?1 – ?2. (Use 2 decimal places.) lower limit =__ upper limit =__
A random sample of 390 married couples found that 284 had two or more personality preferences in common. In another random sample of 572 married couples, it was found that only 32 had no preferences in common. Let p1 be the population proportion of all married couples who have two or more personality preferences in common. Let p2 be the population proportion of all married couples who have no personality preferences in common.
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The U.S. Geological Survey compiled historical data about Old Faithful Geyser (Yellowstone National Park) from 1870 to 1987. Let x1 be a random variable that represents the time interval (in minutes) between Old Faithful eruptions for the years 1948 to 1952. Based on 9440 observations, the sample mean interval was x1 = 63.6 minutes. Let x2 be a random variable that represents the time interval in minutes between Old Faithful eruptions for the years 1983 to 1987. Based on 24,053 observations, the sample mean time interval was x2 = 72.8 minutes. Historical data suggest that ?1 = 8.21 minutes and ?2 = 12.62 minutes. Let ?1 be the population mean of x1 and let ?2 be the population mean of x2.
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| upper limit | =__ |
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