Please answer using Chi-square and show all the step-by-step solution. Thank you!

 

1. You crossed tall pea plants to another tall pea plants. You collected all the seeds and planted them only to find that the offspring were 69 tall and 27 short pea plants. Determine if the cross follow the Mendelian ratio of 3:1 

 

2. Go to https://www.sciencecourseware.org/FlyLabJS/ and design a fruit fly with the following traits.

1. wild type female with male having vestigial wings and black body, mate the resulting F₁ with another F₁. Determine the goodness of fit of the data observed.

 

3. Determine the probability of the following:

1. A mother just received the news that she is carrying an octuplet, determine the probability that the couple will have equal number of male and female in their children.

• According to Mendalian ratio for monohybrid cross for phenotype = 3:1 and genotype = 1:2:1

• chi square test (X² )is used to detrmine whether there is significant difference between the expected frequencies and the observed in one or more categories.

hence it could be formulised as  X2=(O−E)2/E

where O = OBSERVED VALUE

             E = EXPECTED VALUE

• Probability means possibility. It is expressed from 0 to 1. This is the basic probability theory, which is also used in the probability distribution. 
• Formula:- Probability of event to happen P(E) = No. of favourable outcomes/ Total no. of outcomes

Step-by-step explanation

1. 

Tt * Tt

the offsprings produced = 69 tall and 27 short

as on calculating 27*3= 71 and 69 is approximately equal to 71 so it does follow the Mendalian ratio 

2.

observed female = 495

observed male = 496

total = 991

probability female = 0.4995

probability male = 0.5005

lets hypothyse that male and female ratio is 50% and 50% or 0.5 female an 0.5 male

then expected male = 0.5 *total  = 0.5 * 991 = 495.50

and expected female = 0.5*total = 0.5 * 991 = 495.50

hence chi square = (o−e)2/e

therefore chi for female = (495−495.5)2/991

 chi for female = 0.00

chi for male = (496−495.5)2/991

chi for male = 0.00

total = 0.00

therefore,

chi square test stastics =0.00

degree of freedom = n-1( where n = total no categories-1) = 2-1 =1

and from the table of chi square level of significance = 0.9747

3.

octuplets = 8 childs

therefore probability of having 4 boy = 1/2*1/2*1/2*1/2= 1/16

and hence probability for having 4 girl = 1/2*1/2*1/2*1/2 = 1/16

Finally, I hope that this discription about the mendal ratio, chi square and probability will lower down the confusion. If so please dont forget to give your feedback.