Biology paper 5 doubts

[Mukit-ul Islam]

Well, there were 20 samples for each batch......so 20-1 + 20-1

 

[good man12]

Well, there were 20 samples for each batch......so 20-1 + 20-1

yes, i got 38 too...paper was quite easy, GT will be high

 

[Mukit-ul Islam]

yes, i got 38 too...paper was quite easy, GT will be high

How did you estimate the no of cells in the culture?

 

[good man12]

How did you estimate the no of cells in the culture?

that was very tough, although we coulc estimate number of cells alive and dead to calculate survival rate by using microscope, im not so sure that microscope could be applicable for estimating number of cells, but i just wrote o use a microscope and analyze 0.1 cm cubed of fluid, count number of cells in plane of view and divide by o.1

 

[Mukit-ul Islam]

that was very tough, although we coulc estimate number of cells alive and dead to calculate survival rate by using microscope, im not so sure that microscope could be applicable for estimating number of cells, but i just wrote o use a microscope and analyze 0.1 cm cubed of fluid, count number of cells in plane of view and divide by o.1

i said something like that but than i said find average of the 20 samples and multiply by the total volume of culture

 

[good man12]

i said something like that but than i said find average of the 20 samples and multiply by the total volume of culture

dude,in question it said number of cells per centimetere cubed, they wanted us to tell how we can obtain the values of number of cells.....in a small sample, not for whole batch.

 

[Mukit-ul Islam]

dude,in question it said number of cells per centimetere cubed, they wanted us to tell how we can obtain the values of number of cells.....in a small sample, not for whole batch.

maybe

 

[Nishii]

what was the answer to the second part of the standard deviation question? Suggest a reason why the standard deviation increases with time?

 

[Z.S.M]

what was the answer to the second part of the standard deviation question? Suggest a reason why the standard deviation increases with time?

size of sample increased! values become more spread out around the mean!

 

[Mukit-ul Islam]

what was the answer to the second part of the standard deviation question? Suggest a reason why the standard deviation increases with time?

not too sure but i said that as the no. of thalli increases, it becomes more difficult to count them as they have various sizes of development.

 

[123dawg]

i got 38

I did as well (20-1)+(20-1)

 

[123dawg]

dude,in question it said number of cells per centimetere cubed, they wanted us to tell how we can obtain the values of number of cells.....in a small sample, not for whole batch.

Yea they wanted number of cells in million per cm^3 so I said place a sample on a slide . Then set microscope to high power and using a stage micrometer calibrate the graticule. The use the graticule to calculate the diameter of the field of view. Then using pie.r^2 get the field of view are in cm^3. Then count all cells in field of view and divide by are to get number of cells per cm^3

 

[SincerlyMe]

what was the degrees of freedom, how did u calculated dat?

I did 10-1 + 10-1 and so I got 18 ..

 

[123dawg]

I did 10-1 + 10-1 and so I got 18 ..

Why 10 ? They said the 20 samples from each was taken

 

[good man12]

size of sample increased! values become more spread out around the mean!

yes, numbers involved became larger

 

[confused123]

Why 10 ? They said the 20 samples from each was taken

bachi ki jaan lay ga kya? ho jati hay galti ppr mein, one doesn't makes mistakes on purpose

 

[confused123]

Yea they wanted number of cells in million per cm^3 so I said place a sample on a slide . Then set microscope to high power and using a stage micrometer calibrate the graticule. The use the graticule to calculate the diameter of the field of view. Then using pie.r^2 get the field of view are in cm^3. Then count all cells in field of view and divide by are to get number of cells per cm^3

my answer was pretty similar. and how will you make different concentrations from 4000 dm^-3..?

 

[123dawg]

my answer was pretty similar. and how will you make different concentrations from 4000 dm^-3..?

I said put 20cm^3. Of the 4000 mg dm^-3 in a beaker, take 10 from this and place in another beaker with 10 of pond water and so on, that was the gist of mine