**Cross of true-breeding parents:**

For a dihybrid cross: 9:3:3:1 phenotypic ratio (9 tall+violet : 3 tall+white : 3 dwarf+violet : 1 dwarf+white)

For a monohybrid cross: 3:1 phenotypic ratio (3 tall or violet : 1 dwarf or white)

Total number of offsprings = 80 + 36 + 39 + 5 = **160 flowers**

Expected tall+violet flowers = $160\times \frac{9}{9+3+3+1}$ = **90 flowers**

Expected tall+white flowers = $160\times \frac{3}{9+3+3+1}$ = **30 flowers**

Expected dwarf+violet flowers = $160\times \frac{3}{9+3+3+1}$ = **30 flowers**

Expected dwarf+white flowers = $160\times \frac{1}{9+3+3+1}$ = **10 flowers**

Table of chi-square values

Imagine that you attempted to recreate Mendel's work with garden peas. You began by crossing true breeding violet-flowered, tall plants with white flowered dwarf plants. After self-crossing the F_{1} generation, you obtain the following phenotypes in the F_{2} generation:

80 tall, violet flowers

36 tall, white flowers

39 dwarf, violet flowers

5 dwarf, white flowers

How many tall plants with violet flowers were expected?

How many tall plants with white flowers were expected?

How many dwarf plants with violet flowers were expected?

How many dwarf plants with white flowers were expected?

Use a chi-square analysis to test the hypothesis that the F_{2} data for stem length (tall:dwarf) is consistent with Mendel's law of segregation. Calculate the chi square value.

Use a chi-square analysis to test the hypothesis that the F_{2} data for stem length (tall:dwarf) and flower color (violet:white) is consistent with Mendel's law of independent assortment. Calculate the chi square value.

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