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14 Cards in this Set
- Front
- Back
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what are the three objective of chi square?
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1. determine if experimental data constitutes a good fit to an expected ratio or value
2. to interpret a chi square value in terms of probability of an event occurring 3. to identify the null and alternative hypothesis when using a chi square test |
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why do we use a chi square?
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it is used to provide an estimate of the probability that an observed value did or did not occur by chance alone.
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what would be the question in the case of the bird case?
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were the observed value due to chance occurrence or is there actually a difference in the gender ration of the bird?
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what is the formula?
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SUM OF (OBSERVED MINUS EXPECTED)SQUARED DIVIDED BY EXPECTED
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what p value is generally the cut off between values that are significant and non significant ?
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.05
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p stands for..
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probability
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.5 and .7 is greater that .05 therefore what can we say?
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not significant
therefore due to normal chance and is not due to some other force since the ratio of 48:52 is not significantly different than a ratio of 50:50 |
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null hypothesis
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there is no significant difference between the observed and expected values
the variability we observed in coin tossing is due to chance since our values are not significantly different |
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alternative hypothesis
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there is a significant different between the observed and expected values
the variability we observed in coin tossing is due to some other factor since our values are significantly different |
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why are corn ears excellent models for mendelian genetics?
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because each kernel represents an independent crossing event
therefore each corn ear represents 100s of independent crossings |
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mendel's law of random segregation: 3 things
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1. diploid germ line cells of sexually reproducing species contain two copies of almost every chromosomal gene
2. the two copies are located on members of a homologous chromosome pair 3. during meiosis, the two copies separate, so that a gamete receives only one copy of each gene |
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random segregation can be demonstrated by a
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monohybrid cross
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according to the law the random segration, each female gamete receives one copy of R allele when it is formed from meiosis
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each pollen gram or male gamete receives the r allele there fore the offspring of the cross must be heterozygous
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mendels law of independent assortment
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when the alleles of two different genes separate during they do so independently of one another
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