210800
Description
Mind Map by shirley.ha, updated more than 1 year ago
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Created by shirley.ha
about 11 years ago
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CI
- level of confidence of 95% (±1.96 standard errors) is a
convenient level for conducting scientific research, so it is
used almost universally
- Note that the 95% CI is statistically the same
as setting the p-value as p = 0.05.
- can be set at other levels, e.g. 99% (±2.57
standard errors) but the 95% CI is the
standard one used by most researchers.
- are used for hypothesis testing but are also
useful because they demonstrate how small or
large the true effect size might be.
- can be set at other levels, e.g. 99% (±2.57
standard errors) but the 95% CI is the
standard one used by most researchers.
- Note that the 95% CI is statistically the same
as setting the p-value as p = 0.05.
- following quantities make up and influence a
confidence interval and are most important if you
are to correctly interpret CIs in research articles:
- a. The sample mean (or proportion)
- determines the location or middle of the confidence interval
- determines the location or middle of the confidence interval
- b. The sample size (n).
- number (n) in the sample increases, the width of the CI gets narrower
- often described as the “power” of the study
- it reflects the importance of large numbers of
participants in a study sample.
- narrower the CI, the more certain one can be
about the size of the true effect.
- narrower the CI, the more certain one can be
about the size of the true effect.
- it reflects the importance of large numbers of
participants in a study sample.
- If a study reports a 95% CI then means that
there is a 95% chance that the true result lies
within the CI.
- As the confidence interval gets smaller, the
width of the CI gets narrower and your
confidence in the results increases.
- As the confidence interval gets smaller, the
width of the CI gets narrower and your
confidence in the results increases.
- number (n) in the sample increases, the width of the CI gets narrower
- c. The sample standard deviation (s).
- As the s increases, the width of the CI gets wider.
- another way of demonstrating the effect of the sample size on the CI.
- another way of demonstrating the effect of the sample size on the CI.
- As the s increases, the width of the CI gets wider.
- a. The sample mean (or proportion)
- Other factors
- 1. CI for RR and OR:
- If the CI around a RR or OR includes one,
this result is NOT statistically significant
- this is because RR = 1 and OR = 1,
- is the null value for the relative risk and odds ratio.
- is the null value for the relative risk and odds ratio.
- this is because RR = 1 and OR = 1,
- If the CI around a RR or OR includes one,
this result is NOT statistically significant
- 2. CI for the Mean:
- If the CI for the mean (eg difference in
mean scores between two groups)
includes ZERO,
- this result is NOT statistically significant, as the null
value for the mean difference is zero.
- this result is NOT statistically significant, as the null
value for the mean difference is zero.
- If the CI for the mean (eg difference in
mean scores between two groups)
includes ZERO,
- 1. CI for RR and OR:
- state how confident we are that the true population
mean (or proportion) will fall between the lower and
upper limits expressed by the confidence intervals.
- important, because as researchers, we usually deal
with samples from a population
- show the extent to which statistical estimates (from the
sample) could be accurate (or generalisable to the total
population of interest).
- show the extent to which statistical estimates (from the
sample) could be accurate (or generalisable to the total
population of interest).
- important, because as researchers, we usually deal
with samples from a population
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