Question 2

  • Simple Random Sampling

    0 eldwes u0Aelnd0d

  • Stratified Sampling

    C:\\6432CA65\\FE01530B-89BD-4F8B-A3E1-55F12080AD12\_files\\image308.png

  • Systematic Sampling

    Population Sam ple (every 3r )

  • Cluster Sampling

    UZUU 10 11 12 11 12 Sample (2 clusters) Cluster Population

Question 6

Two-tail Two-Tailed P-value = P (Z < —IzolorZ \> Izol) = 2P(Z \> Izol) P-VaIue Approach Assume that the null hypothesis is true. The P-Value is the probability of observing a sample mean that is as or more extreme than the observed. How to compute the P-Value for each type of test: x—go Step 1: Compute the test statistic zo I Zol Right Tail Right-Tailed P-value = \> zo) The area right of zo is the P-value The sum of the area in the tails is the P-value l: 01 The sum of the area in the tails is the P-value Left Tail Left-Tailed P-value = < zo) The area left of is the P-value

Question 14

  • -1 < r < 1

    Formula for the Least Squares Regression Line (I—SRI.) LSRL Formula Slope and Intercept Slope: Intercept — bx Variables in Slope and Intercept Formulas r — correlation coefficient x — mean of independent variable y — mean of dependent variable sr — standard deviation of independent variable sy — standard deviation of dependent variable

Question 15

  • The power of a test is affected by sample size (bigger sample, more power) and alpha level (larger alpha, i.e. .05 compared to .01, more power)

    ![SIGNIF CANCE LEVEL There is a trade-off between the significance level and power: the more stringent (lower) the significance level, the lower the power. Figure 3 shows that power is lower for the 0.01 level than it is for the 0.05 level. Naturally, the stronger the evidence needed to reject the null hypothesis, the lower the chance that the null hypothesis will be rejected. 1.00 0.80 0.60 0 40 0.20 0.00 a = 0.05 a = 0.01 Figure 3. The relationship between significance level and power with one-tailed tests: u = 75, real u = 80, and o =

    1. ](./media/image313.png)

Question 18

the width of a confidence interval is dependent on the z (or t)\* and the standard deviation of the statistic. Assuming the z\* is unchanged, the question is which is the smaller standard deviation sqrt(.7\* .3/50) is approximately 00648 while sqrt(\[37/60\*23/60\]/60) is approximately 0.0628 so the confidence interval based on 37 out of 60 will be slightly narrower than the confidence Interval based on 35 out of 50

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