Biology Forums - Study Force

A 90 confidence interval for a population proportion calculated using data from a random sample of size n = 51 is (0.573, 0.787). Which of the following is the 95 confidence interval calculated from the same data?
  1.(0.602, 0.758)
  2.(0.620, 0.740)
  3.(0.553, 0.807)
  4.(0.543, 0.817)
  5.(0.486, 0.874)

Q. 2

Chuck has decided to increase the size of the sample he uses to estimate a population proportion.
   What is the effect on the width of the associated confidence interval?

  1.The width of the confidence interval increases.
  2.The width of the confidence interval decreases.
  3.The width of the confidence interval is unchanged.
  4.There is not enough information to say.

Q. 3

Jasmine has decided to decrease the confidence level in her estimation of a population proportion. What is the effect on the width of the associated confidence interval?
  1.The width of the confidence interval increases.
  2.The width of the confidence interval decreases.
  3.The width of the confidence interval is unchanged.
  4.There is not enough information to say.

Q. 4

An unbiased statistic is one that
  1.is closely approximated by a normal curve.
  2.has the smallest variance.
  3.is mound-shaped.
  4.is nearly symmetric.
  5.does not consistently tend to underestimate or to overestimate the value of a population characteristic.

Q. 5

A random sample will be selected from the population of all adult residents of a particular city. The sample proportion will be used to estimate p, the proportion of all adult residents who are registered to vote. For which of the following situations will the estimate tend to be closest to the actual value of p?
   I. n = 210 and p = 0.6
   II. n = 200 and p = 0.6
   III. n = 200 and p = 0.7

  1.I only
  2.II only
  3.III only
  4.II and II only
  5.All three estimates will be equally close to the actual value of p.

Q. 6

Holding all other elements equal, an increase in sample size will result in a wider confidence interval.
  1.True
  2.False

Q. 7

Using a higher confidence level will result in a narrower confidence interval.
  1.True
  2.False

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