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BIOL 315 Flashcards 4
Cards in this deck (13)
- 1Normal DistributionA continuous, symmetrical distribution that is also called the bell-shaped curve and describes many biological variables. Most observations fall close to the mean and fewer fall away to the mean
- 2Parameters of Normal DistributionMean (can be any integer, positive or negative)
Standard deviation (can be any positive number) - 3Properties of the Normal DistributionContinuous
Symmetrical
Single-mode (mean=median=mode)
2/3 area lies within one standard deviation of the mean
95% of the area lies within 1.96 standard deviations of the mean - 4Standard Normal DistributionAlso called the Z-distribution. A type of normal distribution where the mean is 0 and the standard deviation is 1. Any values from a normal distribution can be converted to a standard normal distribution by using the equation for the standard normal deviate
- 5Central Limit TheoremTells us that the mean of a large number of measurements is approximately normally distribution. Assumptions are that samples were random. Sample can be taken from a normal OR A NON-NORMAL population
- 6t-DistributionsAre very similar to the normal distribution, except the standard error of the mean is estimated, and as a consequence it is more spread out than the Z-distribution. It has a lower peak and fatter tails—though as the degrees of freedom increase, the t-distribution more closely resembles the standard normal distribution
- 7One-Sample t-TestCompares the mean of a random sample from a normal population with a population mean. The null hypothesis is usually that the population mean = µ. Assumes random sampling and that the variable is normally distributed in the population
- 8Paired SamplesA type of experimental design where both treatments are applied to every sampling unit. Every member of the pair shares commonalities except for the tested categorical variable. Accounts for extraneous variation and increases power.
- 9Paired t-TestA special case of the one-sample t-test that tests if the mean difference between paired measurements is zero (null hypothesis µ=0). Assumes the same as one-sample t-test but in respect to the differences: normally distributed differences and independent differences
- 10Standard Normal Deviate (Z)Tells us how many standard deviations a particular value is from the mean (with reference to a standard normal distribution)
- 11Degrees of FreedomDescribes the number of values in a calculation that are free to vary (this is one less than the amount measured)
- 12Critical ValuesEvery t-distribution has its own critical 5% t-value that depends on the number of degrees of freedom. If the value of t is greater than the critical value, then we can reject null hypothesis. If the value of t is less than the critical value, then we fail to reject null hypothesis
- 13Independent SamplesWhen the samples do not influence or affect the probability of choosing other samples. You get independent samples when you sample randomly.
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- Science (Bio 315) Flashcards on BIOL 315 Flashcards 4, created by Natasha Gidluck on 29/10/2020.
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