Question 1
When testing whether two population variances are equal, if the sample sizes aren1= 8 andn2= 10, the number of degrees of freedom will be:
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7 and 9.
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8 and 10.
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9 and 11.
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None of the above.
Question 2
When two independent random samples of sizesn1andn2have been selected from populations with meansμ1andμ2and variances\(\style{font-family:Times New Roman;}{\sigma_1^2}\)and\(\style{font-family:Times New Roman;}{\sigma_2^2,}\)which of the following statements is true?
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If the sampled populations are normally distributed, then the sampling distribution of\(\style{font-family:Times New Roman;}{{\overline x}_1-{\overline x}_2}\)is exactly normal only whenn1andn2are both at least 30.
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If the sampled populations are normally distributed, then the sampling distribution of\(\style{font-family:Times New Roman;}{{\overline x}_1-{\overline x}_2}\)is normal regardless of the sample sizes.
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If the sampled populations arenotnormally distributed, then the sampling distribution of\(\style{font-family:Times New Roman;}{{\overline x}_1-{\overline x}_2}\)is normal regardless of the sample sizes.
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If the sampled populations are normally distributed, then the sampling distribution of\(\style{font-family:Times New Roman;}{{\overline x}_1-{\overline x}_2}\)is approximately normal only ifn1+n2≥ 30.
Four hypotheses on how populations might relate to one another along an environmental gradient.
Independent Assortment
Selected Adjuncts to Anesthesia
Selected Drugs Suspected of Causing Cancer in Humans
Selected Combination Medications for Hypertension
Selected Calcium Salts