The lengths of text messages are normally distributed with a population standard deviation of 3 characters and an unknown population mean. If a random sample of 29 text messages is taken and results in a sample mean of 27 characters, find a 80% confidence interval for the population mean. Round your answers to two decimal places. z0.10 z0.05 z0.04 z0.025 z0.01 z0.005 1.282 1.645 1.751 1.960 2.326 2.576 You may use a calculator or the common z-values above. Select the correct answer below: (26.29, 27.71) (25.56, 28.44) (26.02, 27.98) (25.91, 28.09) (25.70, 28.30) (26.08, 27.92)
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We are given that the lengths of text messages are normally distributed with a population standard deviation of $\sigma = 3$ characters and an unknown population mean $\mu$. A random sample of $n = 29$ text messages is taken, resulting in a sample mean of $\bar{x} Show more…
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The lengths of text messages are normally distributed with a population standard deviation of 6 characters and an unknown population mean. If a random sample of 27 text messages is taken and results in a sample mean of 25 characters, find a 95% confidence interval for the population mean. Round your answers to two decimal places. z0.10 z0.05 z0.04 z0.025 z0.01 z0.005 1.282 1.645 1.751 1.960 2.326 2.576 You may use a calculator or the common z-values above.
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The lengths of text messages are normally distributed with a population standard deviation of 5 characters and an unknown population mean. If a random sample of 26 text messages is taken and results in a sample mean of 24 characters, find a 92% confidence interval for the population mean. Round your answers to two decimal places. z0.10 z0.05 z0.04 z0.025 z0.01 z0.005 1.282 1.645 1.751 1.960 2.326 2.576 You may use a calculator or the common z-values above. Select the correct answer below: (21.96,26.04) (22.66,25.34) (21.31,26.69) (22.39,25.61) (21.57,26.43) (22.28,25.72)
Kari H.
The lengths of text messages have an unknown distribution with mean 26 and standard deviation 5 characters. A sample, with size n = 40, is randomly drawn from the population and the mean is taken. What is the probability that the mean is more than 25.4 characters? z | 0.00 | 0.01 | 0.02 | 0.03 | 0.04 | 0.05 | 0.06 | 0.07 | 0.08 | 0.09 -1.0 | 0.1587 | 0.1562 | 0.1539 | 0.1515 | 0.1492 | 0.1469 | 0.1446 | 0.1423 | 0.1401 | 0.1379 -0.9 | 0.1841 | 0.1814 | 0.1788 | 0.1762 | 0.1736 | 0.1711 | 0.1685 | 0.1660 | 0.1635 | 0.1611 -0.8 | 0.2119 | 0.2090 | 0.2061 | 0.2033 | 0.2005 | 0.1977 | 0.1949 | 0.1922 | 0.1894 | 0.1867 -0.7 | 0.2420 | 0.2389 | 0.2358 | 0.2327 | 0.2296 | 0.2266 | 0.2236 | 0.2206 | 0.2177 | 0.2148 You may use a calculator or the portion of the z-table given above. Select the correct answer below: 0.100 0.151
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