Covid-`9 Analysis : Mexico & Chile

Table showing with Covid-19 confirmed cases  with Recoveries in Chile  and Mexicoas on July 22, 2020

As on July 22, 2020
	Confirmed		REcovered
	Cases		Cases
Chile	334,683		306,816
Mexico	356,255		227,165
Source:  Worldometer

Let p₁ and p₂ be the proportion of recoveries to confirmed cases of Covid-19.

We set Null Hypothesis H₀: p₁ = p₂                                                                                                                                                                             Then the Alternative Hypothesis is H_1:: p₁ # p₂      

We have, p = (n₁p₁+n₂p₂)/(n₁+n₂) and S.E. of (p₁-p₂) = √(pq)(1/n₁+1/n₂)

                                                Z = |p₁-p₂|/S.E. of (p₁-p₂) 

n1=	334,683		p1=	0.916736		1/n1=	2.9879E-06
n2=	356255		p2=	0.637647		`/n2=	2.80698E-06
a1=	306,816			p=	0.773	q=	0.227
a2=	227165				√pq(1/n1+1/n2)=		0.00100864
1/n1+1/n2	5.79488E-06			|p1-p2|=	0.279089
			z =	276.70

Z = 2.58 at 1% level of significance. As z(obs) = 276.70, the Null Hypothesis is rejected

It is concluded that the Recovery rate due to Covid-19 is significantly higher in Chile than in Mexico.

Covid-19 in USA and Brazil as on July 8, 2020

Table showing with Covid-19 confirmed cases  with deaths in USA and Brazil as on July 8, 2020

		Confirmed		Deaths
USA		2923432		129963
Brazil		1623284		65487

Source: WHO

Let P₁ and P₂ be the proportion of deaths to confirmed cases of Covid-19.

We set Null Hypothesis H₀: P₁ = P₂                                                                                                                                                                             Then the Alternative Hypothesis is H_1:: P₁ # P₂      

We have, p = (n₁p₁+n₂p₂)/(n₁+n₂) and S.E. of (p₁-p₂) = √(pq)(1/n₁+1/n₂)

                                                Z = |p₁-p₂|/S.E. of (p₁-p₂)

USA			2923432				129963
Brazil			1623284				65487
			4546716				195450
n1=	2923432			p1=		0.044456				1/n1=		3.42064E-07
n2=	1623284			p2=		0.040342				`/n2=		6.16035E-07
a1=	129963					p=		0.043		q=		0.957
a2=	65487							√pq(1/n1+1/n2)=				0.000198533
1/n1+1/n2	9.58099E-07
						|p1-p2|=		0.004113
										Z=		20.72

|z| = 2.58 at 1% level of significance.  We reject the Null Hypothesis H₀ as  obs|z| = 20.72 and conclude that proportion of deaths due to Covid-19 is significantly higher in USA than in Brazil.

Revised Analysis of Covid-19 of USA and UK

Table showing with Covid-19 confirmed cases  with deaths in USA and UK as on July 8, 2020

		Confirmed		Deaths
USA		2923432		129963
UK		286353		44391
	Total	3209785		174354

Source: WHO

Let P₁ and P₂ be the proportion of deaths to confirmed cases of Covid-19.

We set Null Hypothesis H₀: P₁ = P₂                                                                                                                                                                             Then the Alternative Hypothesis is H_1:: P₁ # P₂      

We have, p = (n₁p₁+n₂p₂)/(n₁+n₂) and S.E. of (p₁-p₂) = √(pq)(1/n₁+1/n₂)

                                                Z = |p₁-p₂|/S.E. of (p₁-p₂)  

n1 =	n1=	2923432	p1 =	0.044456	n2 =	286353	p2 =	0.155022
	a1=	129963			a2=	44391
1/n1=	3.42064E-07		p=	0.054	q =	0.946
1/n2=	3.49219E-06	|p1-p2|=	0.11056632
1/n1+1/n2=	3.83426E-06	p*q =	0.05136892	(1/n1+1/n2) =			3.83426E-06
		=	0.000444				=
		S.E. of (p1-p2) =		0.000444
			|z|=	249.13	=

|z| = 2.58 at 1% level of significance.  We reject the Null Hypothesis H₀ as  obs|z| = 249.13 and conclude that proportion of deaths due to Covid-19 is significantly higher in U.K. than in USA.